***First Lecture

Antypyretic. Answer either (1) Why would you take such a drug? or (2) What is the best known example of such a drug.

to reduce fever, aspirin

Referring to the body's thermostat, under the same circumstances when an animal might utilize vasoconstriction, what would happen to its fur?

piloerection, fluffing up the fur for better insulation

Guilleman and Schally needed a quarter of a million hypothalami to isolate TRH. Why did it take so many?

there is not much TRH because of the portal delivery

What happens at the ribosome is called translation. Then why (for what process) is the Golgi apparatus required?

post-translational modifications

"A large fraction of the ATP is made in the mitochondrion." What process makes the ATP that is not made in the mitochondrion?


"A hormone is diluted by the blood stream, and so a lot more chemical signal is needed than for the a neurotransmitter from the spinal motor neuron to the muscle cell." Why is a smaller amount of hormone required when the hypothalamus signals to the anterior pituitary?

the portal system delivers it more discreetly

An equivalent circuit is used as a model that explains exponential functions of voltage as a function of distance along the axon or voltage as a function of time when a square wave of current is applied. Name one of the electrical components used in such an equivalent circuit.

batteries, resistors, capacitors

Before iodized salt, people who lived where would have been more likely to develop goiter?

inland (away from the ocean)

How would high dietary overdoses of iodine help some people and under what circumstances?

if exposed to radioactive iodine from a reactor leak, normal iodine would compete for incorporation into thyroxine

How come there is heat available to allow you to regulate your body temperature at 98.6 o F?
catabolism is only about 40 % effective in useful work, the "waste" is heat that can be used
"The nucleus orchestrates the cell's functions by [doing what?] at the level of the ribosomes?
(via mRNA) translation of proteins
What would vasoconstriction do to help to regulate body temperature?
decrease heat loss
4. Used as an example of homeostasis, thyroxine was shown to have what effect on the anterior pituitary?
"inhibits responsiveness to TRH" translates to: feeds back to decrease release of TSH

An equivalent circuit for the membrane, shown in the first lecture, plotted an exponential decrement of voltage as a function of distance. Name one of the electrical components that was shown in that model.

resistor, capacitor, battery

Using an expression that relates to constructive metabolic reactions and the chemical nature of the compounds, what are the testosterone-like drugs that some athletes abuse?

anabolic steroids

It's winter and it is cold outside, and your home heating system serves as a model of homeostasis. A furnace provides heat, "feedback" in the homeostasis model. Temperature is monitored by a thermometer. What is the other critical component in this model of homeostasis?

the set-point on the thermostat, a comparator

Why are the various types of insensible water loss (recall that dogs and humans were used as examples) so effective and critical in temperature regulation?

sweating or panting

Near the kidney is an endocrine gland that surrounds the adrenal medulla. Answer one of the following: (1) What is the name (abbreviation will suffice) of the pituitary peptide that regulates a major hormone (cortisol) from this gland? (2) What kind of chemical is this gland's hormone (cortisol)?

ACTH, steroid

"Hormones are not very efficient because they get diluted by the entire volume of the blood stream." Why are releasing hormones (releasing factors) from the hypothalamus different?

They travel by the portal system directly to the pituitary

Hypertrophy of the thyroid gland Answer one of the following: (1) results from insufficiency of what dietary substance? (2) results from insufficiency of what hormone? (3) is called (what)? (4) is referred to as endemic (why)?

iodine, thyroxine (T3 or T4), goiter, happened inland, not in coastal areas

Under what circumstances does a person lose calories via the urine?

untreated diabetes

What is an anabolic steroid?

a hormone like testosterone that bromotes muscle growth

Why might you take iodine supplements if you are downwind of a reactor accident?

have more "cold" iodine to compete with radioactive iodine for T3 and T4 incorporation

"Tropic," the "T" in "ACTH" means affecting the activity of. Specifically, on what gland does ACTH have this trophic affect? (i.e. What does the AC stand for?)

adrenal cortex

What does piloerection do to regulate back to the set point?

fluffing the fur prevents heat loss

Name a substance for which the portal vessel from the hypothalamus to the pituitary is specifically "designed."

TRH, others like it

What does panting achieve for a dog?

evaporative cooling

ACTH triggers the release of what hormone from its target gland?


Relate the statement "Aspirin is an antipyretic" to the concept of homeostasis.

pyrogens reset the thermostat to cause fever

"Insensible" is a term applied to water loss by perspiration or panting in contrast with the water loss by micturition. What does "insensible" mean?

you're not aware of it

Relate the amount of energy an average adult uses per day in catabolic metabolism to the energy needed to increase the temperature of 1 ml of water by 1 degree C.

2000 k cal / day relative to the definition of one calorie

What is the set point for the human hypothalamic thermostat in degrees C?


Why are sweating and panting so effective for increasing heat loss?

the heat of vaporization is 540 cal

Why is the term "anabolic" applied to steroids abused by some athletes?

they cause build-up as oppoaed to break-down (in catabolism), in this case of muscle mass

How does aspirin affect the set point of the thermostat?

it is antipyretic

What would be specified with the term "catabolism" in distinction with the more general term "metabolism?"


How does vasoconstriction decrease heat loss?

Less radiation of warmth from extremeties

Why is testosterone referred to as an "anabolic steroid?"

it favors muscle growth

If there were a deficiency of iodine in the diet, which pituitary hormone would be produced in excess, leading to goiter?


ACTH has a negative feedback to control what hypothalamic hormone in order to regulate its own (ACTH's) level?


Why is it especially useful for a person to sweat when hot?

Evaporative heat loss

In terms of the human thermostat, when would shivering be a useful behavior?

Muscle activity generates heat

"You do not lose calories through your feces and urine." What is the most notable exception to this generalization?

Untreated diabetes mellitus

Why don't most people gain or lose a lot of weight rapidly?

homeostasis - they eat the right amount

State one of the physiological mechanisms for decreasing heat loss in mammals.

piloerection, vasoconstriction

Why are some steroids are called "anabolic?"

they favor growth

"Neurotransmitters are strategic because they are so discrete and thus use a minimum amount." Why on earth would there be hormones then?

they reach many areas

How does glucose get into the cell?

transport, facilitated and co-transport with sodium

What hormone does the adrenal release in response to ACTH?


There is a lot less TRH than TSH. Why?

TRH delivered neatly via portal system

How is paracrine signaling distinguished from endocrine signaling?

paracrine is local

Why is panting and perspiring so effective to increase heat loss?

because of the large heat of vaporization of water

A fat is a triglyceride. How come membrane lipids have only two fatty acids in text book diagrams? (i.e. What is the third item linked to the glycerol?)

the polar head group

"Endemic" was the term your text used for (what?) disorder of inland people who had no seafood (in the old days)?


The lay expression for ectotherm is "cold-blooded." Why is that inaccurate?

More like they assume ambient temperature

How come homeotherms (endotherms) always have heat available for maintaining body temperature at the set point?

Because of inefficiency in metabolism, waste is heat

In addition to triiodothyroxine, what is the other thyroid hormone?


In your homeostasis lecture, ACTH was used as an example. What keeps ACTH levels from getting real high?

homeostasis (negative feedback from cortisol)

Adrenalin comes from the adrenal medulla. By contrast, where does ACTH exert its trophic effect?

adrenal cortex

What is the opposite of vasodilation and what is this (the opposite of vasodilation) useful for (in terms of homeostasis)?

vasoconstriction would decrease heat loss (body's thermostat)

A diagram from the introductory biology book showed how hypothalamic CRF (corticotropin releasing factor) caused the anterior pituitary to secrete ACTH (adrenocorticotropic hormone). Why is this hormone referred to as CRF?

corticotropin = ACTH, factor=hormone, causes its release

Guillemin and Schally won a Nobel Prize for for their discovery of releasing hormones (factors), a heroic task because they are present in vanishingly small amounts. Why can there be such small amounts of these hormones (compared with other hormones).

portal vessel delivers it without dilution

A nuclear reactor spews out radioactivity upwind of where you live. Quick! What should you eat to minimize thyroid damage?

nonradioactive iodine to compete with the radioactive for uptake

Relate "goose bumps" with temperature regulation in a mammal that has fur.

piloerection would fluff up the fur to conserve heat, goose bumps just show the smooth muscle poking up the "vestigial" hairs

The drugs that some athletes abuse are sometimes called anabolic steroids. What does the word "anabolic" imply?

anabolic (vs catabolic) is the branch of metabolism for constructive reactions

A model for the exponential decrement of voltage along the length of the axon was shown in the first lecture. I said "along the length of the axoplasm, there is resistanceäout in the extracellular space there is resistance but not much." Why isnt there much?
Because there is not a confined space
"The action potential depolarizes the axon ahead of it to the threshold (for the action potential, and how far this spreads is described by an exponential drop-off." What does myelin do to this distance?
Increases it
The drugs that some athletes abuse are sometimes called anabolic steroids. What does the word "anabolic" imply?
Anabolic refers to build-up
"The adrenal is two glands; The adrenal medulla releases adrenaline." The other part: Answer either (1) what is it called? Or (2) what does it release?
1 adrenal cortex 2 cortisol (and others)
Regarding the regulation of blood flow to your periphery, for instance your hands, how would this contribute to temperature regulation?
Radiate more heat if vasodilation
Goiter. Answer either (1) This is caused by too MUCH of what hormone? Or (2) Why is there too much of this hormone?
1 TSH 2 insufficient T3 & T4 -> insufficient negative feedback
What is different about the circulatory system of the hypothalamus - anterior pituitary than most other parts of the body?
Portal system


The introductory book's transparency indicated that "GLUT-1 facilitates glucose diffusion." Answer either why they selected the words (1) "facilitates," or (2) "diffusion."

(1) glucose needs a path across the membrane, (2) but it is not a pump that requires energy

In the phosphoinositide signal transduction cascade, IP3 gates a channel. Answer either (1) Where (specifically)? Or (2) For what ion?

(1) a smooth endoplasmic reticulum (2) calcium ions

Answer either (1) Why are there rainbow colors on a drop of oil on a rain-wet road? or (2) Why are rhodopsin or hemoglobin colored molecules?

(1) from optics of layers that are different thicknesses (2) the protein has a chromophore that makes the protein colored

"A semipermeable membrane is part of the explanation for osmosis." Permeable to what and not permeable to what?

permeable to water but not to a larger molecule like sugar

"Picture an area where the gravel has been lightly shadowed by a light snow blowing from one direction." Answer either (1) What is this technique called? (2) What do the P-face particles represent? or (3) What heavy metal is used for shadowing?

1 freeze fracture 2 membrane proteins 3 platinum

A slide was shown where all the phospholipids of the Drosophila headwhich had been separated were clearly visualized. Answer either (1) What is the name of this technique? or (2) How come these phospholipids could be clearly visualized?

1 autoradiography (thin layer chromatography) 2 they radioactive and the radioactivity exposes photographic film

Tay Sachs disease: Answer either (1) Why is it called a lysosomal storage disease? (2) What molecule fails to turn over? or (3) Why would the eye and brain be affected first?

1 the substance the lysosomes fail to degrade accumulate in lysosomes 2 a glycolipid 3 there are lots of membranes with lots of membrane lipids

In terms of how they mediate signal transduction, state, in simple terms, the fundamental difference between a G protein coupled receptor and the nicotinic acetylcholine receptor.

GPCR leads to transduction cascade and "second messenger" while NAChR is a channel

In "receptor mediated endocytosis," the pit (that becomes a vesicle) has a receptor (like the receptor for LDL) plus what famous protein that makes these pits and vesicles look the way they do in the electron microscope?


"In an isotonic milieu like the blood stream, a red blood cell's shape remains unchanged." To make red blood cell ghosts, Gorter and Grendel Answer one of the following: (1) They moved the cells from an isotonic solution to what kind of solution? (2) What famous membrane transport process mediated the net influx of water into the cell?

hypotonic (distilled water), osmosis

In the third lecture, the importance of G protein coupled receptors (GPCR) was introduced. Where, in the ultrastructural anatomy of either a rod cell or a cell involved in phosphoinositide signaling, would you find a GPCR?

membrane disks in rod, on the plasmalemma (cell membrane

How much energy, delivered by ATP, is used by the GLUT-1 transporter to get glucose into the cell?


In contrast with the G protein coupled receptor, why is the nicotinic receptor more direct?

an ion channel is more direct than a signal transduction cascade

In addition to glycolipids and cholesterol, what is the major lipid constituent of the cell membrane?


In addition to the receptor, in receptor-mediated endocytosis, what famous protein is seen in transmission electron micrographs that gives coated pits and coated vesicles their names?


How much ATP would a cell use to open and close the nicotinic receptor?


"IP3 is a ligand for a calcium channel." Answer one of the following: (1) Where is this Ca2+ channel? (2) Where was the precursor of IP3 (the molecule from which IP3was formed by the action of PLC [phospholipase C])?
(1) on a smooth endoplasmic reticulum, a calcium sequestering cistern (2) PIP2 is a membrane phospholipid
"Vitamin A deprivation decreases the number of bumps seen in fruit fly photoreceptor membranes (transmission electron microscopy of freeze fracture replicas)." These bumps are a visualization of what molecule?
Note that ATP is not used in a channel like the nicotinic receptor that can be closed or, when opened, passes K+ and Na+ (causing depolarization). Where, if at all, is ATP utilized in generating membrane potentials based on K+ and Na+?
Working in the background, the Na+ - K+ ATPase establishes Na+ and K+ gradients

Why do you need lead, osmium, uranium or platinum to see aspects of membrane structure in the electron microscope?

heavy metals are electron dense

What did hypotonic shock do to what kind of cells to allow Gorter and Grendel to show that there was enough lipid in the membrane to make two layers?

burst red blood cells to make red blood cell ghosts with a measured membrane surface area

Why do you need a chromophore (such as retinal for rhodopsin and heme for hemoglobin) to make a protein into a pigment?

proteins do not absorb visible light

How does a steroid hormone get into a cell?

that can pass the lipid barrier

How do sodium ions get forced out of the cell?

active transport with a protein that uses ATP

The nicotinic receptor is a cation channel for what two ions?

K+ and Na+

Rhodopsin and neurotransmitter and hormone receptors interact with what downstrean heterotrimeric protein?

the G protein

What do you call electrical junctions from cell to cell with channels composed of hexamers of connexin protein in register?

gap junctions

What must be bound to the G-protein-coupled-receptor protein to make the fully-functional rhodopsin molecule that absorbs light?


As a result of phospholipase C (PLC) activation, what ion is released into the cytoplasm from smooth endoplasmic reticulum?


In what fundamental way does the location of a steroid hormone receptor differ from that of the receptor for epinephrine?

steroid receptor is in cell, epinephrine receptor is in membrane

In a "cartoon" of a membrane phospholipid, there is a ball with two tails. The ball is the polar (hydrophilic) head group. What are the two tails?

fatty acids (acyl groups)

Which direction does the ATPase pump sodium ions?

out of the cell

Epinephrine binds one G protein-coupled receptor (GPCR). What other GPCR, used for vision, is a pigment that contains a form of vitamin A?


What is the name of the electrical connection between myocardial cells composed of connexin proteins?

gap junction

Why does an erythrocyte turn into an erythrocyte ghost when placed into distilled water?

because of osmosis, it swells and bursts

When a membrane lipid is drawn as a ball with two sticks in a diagram, what are the ball and sticks respectively?

polar head group, fatty acids

One signal transduction product of phospholipase C (PLC), diacylglycerol (DAG), is in the membrane while the other, IP3, inositol trisphosphate, goes into the cytoplasm. Where is the precursor, PIP2 (phosphatidylinositol-4,5-bisphosphate)?

it is a membrane phospholipid

When the nicotinic acetylcholine receptor channel opens, there is an efflux of K+. Why?

because it allows Na+ and K+, so K+ goes down its chemical gradient

One membrane protein is sometimes called the Na+-K+-ATPase. What is its function?

pumps Na+ out, K+ in

What is the function of a hexamer of connexin proteins in one cell's membrane in register with a similar hexamer on the adjacent cell?

gap junction connects adjacent cells' cytoplasm and passes current

How can it be that a cortisol receptor is intracellular while so many hormone receptors, for instance for epinephrine, are on the membrane?

steroids pass through the membrane

Robertson's pioneering electron microscopy paved the way for Davson and Danielli's bilayer membrane model and Sanger and Nicolson's fluid mosaic model. Why were heavy metals like osmium necessary for that demonstration?

Electron dense

If water and ions are excluded from the center of the membrane, where fatty acids reside, how is it that a G protein-coupled receptor can span the membrane?

There are hydrophobic amino acids

Tay-Sachs disease is a fatal autosomal lysosomal storage disease. What accumulates?


Before I introduced metabotropic receptors (G protein coupled proteins that bind a ligand such as a neurotransmitter), I showed rhodopsin, the prototypical G protein coupled receptor. Why doesn't rhodopsin need to have a ligand bind to it? (i.e. What does it have that a neurotransmitter receptor does not have?)

it has retinal, a vitamin A derivative

Researchers have been able to make artificial membranes out of phospholipids in a hole between two compartments in a water bath. Why would membrane lipids naturally arrange themselves as they are aligned in membranes?

polar heads would orient to water and hydrophobic tails toward eachother

In the phosphoinositide signal cascade, phospholipase C (PLC) makes "second messengers" IP3 (inositol trisphosphate, the polar head group) and what(?) from the membrane lipid PIP2 (phosphatidylinositol-4,5-bisphosphate.) [If you do not remember, I have put enough information into the question that you should be able to figure it out.]

diacyl glycerol

Osmosis was referred to as passive transport. Is the sodium-potassium pump passive? Justify.

no, it is active b/c it uses ATP

After feeding radioactive phosphate, extracted lipids were visualized by audioradiography of a TLC (thin layer chromatography) plate. Why didn't I see the sort of lipids that accumulate in Tay Sachs disease?

it is glycolipids and would not take up phosphate

If you fracture a frozen membrane, proteins are exposed. But you cannot see them in the transmission electron microscope unless you do something. What?

you need to make a replica, shadow it from an angle with an electron dense material (platinum)

Under what circumstances (what do you do?) does a passive process (what process?) let you make a red blood cell ghost from a red blood cell?

Put r.b.c into distilled water, osmosis

Tell me about a famous lysosomal storage disease. Your answer can be biochemical, cell biological, or genetic.

Tay Sachs fails to break down a glycolipid that accumulates in the cell, autosomal recessive carried in Ashkenaze Jews

In the transmission electron microscope, what membrane specialization of receptor mediated endocytosis is visualized?

Clathrin coated pits (vesicles)

"11-cis retinal (a bent form of the aldehyde of vitamin A) is the chromophore of rhodopsin." In terms of the molecule's interaction with visible light, what does this mean.
Gives the protein its property of absorbing visible light
"The two half leaflets of the membrane, as seen in freeze-fracture, are called P- and E-faces." Answer either (1) why P and E? or (2) describe why these two halves are distinct from each other.
1 protoplasmic (on the cell side) exoplasmic (the external side), 2 turns out that the proteins are usually seen on the P-face
"Diacyl glycerol." Explain how this name, by itself, would tell you what would have had to happen to a membrane phospholipid to make diacyl glycerol.
2 farry acids (acyl groups) attached to a glycerol means that the polar head group had been chopped off
Tell me how autoradiography of a TLC (thin layer chromatography) plate can help you identify the numerous phospholipids of the cell membrane.
A TLC plate separates lipids, labeling with radioactive phosphate allows exposure of an audorad
"IP3 is a ligand for...," answer either (1) What kind of molecule? Or (2) Where is the molecule (that it is a ligand for)?
1 channel for calcium ion 2 on a smooth ER that sequesters calcium

Extracts from what kind of cell gave the original demonstration that there was enough lipid in a cell membrane to make two layers?


What must be true about the amino acids of the alpha helix of rhodopsin that would let it cross the membrane?

they would be hydrophobic

For Tay-Sach's disease, answer either (1) Why is it called a "lysosomal storage disease?" (2) What molecule is missing because of the mutation? Or (3) What type of molecule is not broken down?

(3) glycolipids are not broken down because of (2) an enzyme deficiency leading to (1) accumulation

In signal transduction cascades, what protein binds to either GTP or GDP.

G protein sepcifically the alpha subunit

***Bioelectric potentials

Graded potentials can be added to each other. What is the expression used to describe an action potential that relates to the statement that "you cannot add one action potential onto the top of another?"


Why is it more useful to use conductance rather than resistance in discussing membranes or membrane channels?

electrical conductance more intuitively relates to ion permeability

Reminder: The Goldman equation looks like the Nernst equation except that it includes concentrations (in and out) plus permeabilities for all three ions - Na+, K+ and Cl-. Only one of these 9 values changes at the beginning of the action potential. Which?

permeability for Na+

What would a hyperpolarizing graded potential do to the probability that a spike would be fired at the axon hillock?

decrease probability

"Potential is equal and opposite to chemical gradient." Answer either (1) What was assumed? or (2) Who won the Nobel Prize in Chemistry for doing this derivation?

1 energies of two compartments are equal 2 Nernst

Voltage is shown to change as an exponential function of time because of what particular component in an equivalent circuit model?


"Invertebrate axons propagate faster with increasing size with diminishing returns." Answer either (1) What specifically relates to radius (Don't just repeat velocity of propagation)? or (2) Why diminishing returns?

1 space (length) constant 2 it increases with the square root of the radius

"The AC Wheatstone bridge Cole and Curtis used went out of balance indicating that the 'unknown' resistor changed." Answer either (1) What was this resistor? or (2) When did it go out of balance?

1 the axon membrane's resistance 2 when there was an action potential

E=IR. Answer one of these. (1) What are the units for E? (2) What are the units for I? (3) What are the units for R? (4) What is this relationship called?
(1) Volts (2) Amps (3) Ohms (4) Ohm's law
9. After the equilibrium assumption in the derivation of the Nernst equation, the chemical gradient is shown to be equal and opposite to (what)?
Voltage (electrical gradient)

In a simple circuit with a battery connected to the resistor, what is the slope of the line if amperes are plotted on the ordinate (Y-axis) and volts are plotted on the abscissa (X-axis)?

conductance (Siemens)

An exponential change in membrane voltage as a function of time is caused by what electrical property of the membrane?


Voltage arises from either a battery (a source of electromotive force) or (what)?

current flowing through an impedance (such as a resistor)

What is assumed about the total energy (chemical AND electrical) on one side of the membrane vs. on the other side of the membrane to allow Nernst equation to be derived?

the two energies are assumed to be the same

Suppose, with a given set of permeabilities and the standard concentrations, the Goldman equation approximated the resting potential. What would you need to change to calculate the peak of the action potential from the Goldman equation?

increase sodium permeability

Write an equation obeying Ohm's law relating voltage and current but using conductance rather than resistance.

if E=IR (Ohm's law), then E=(1/g)I, so I=GE

What is assumed in the derivation of the Nernst equation?

energy of two compartments is the same which is tantamount to saying that electrical and chemical gradients are equal but opposite

What two components are used in the circuits of high- and low-pass filters to give them the property of having a time constant?

R & C

Permeability to what ion increases at the beginning of the action potential?


Write an equation expressing conductance as a function of resistance.


Faraday's constant (9.65 x 104 Coulombs/mole) is important in expressing electrical component of energy of a thermodynamic system. What do you need to multiply the charge of an individual ion (1.6 x 10-19 Coulombs/ion) by to get Faraday's constant?

Avagadro's number (the number of ions per mole)

What is the name and polarity of the electrode to which cations would migrate in solution?

cathode is negative

After the nerve cell integrates the excitatory and inhibitory post-synaptic potentials, which part of the cell propagates the action potential (if threshold is reached)?


If I graphed Ohm's law with Voltage on the Y axis and current on the X axis, I would get a line. What is the slope?


Invertebrates do not have myelin. What adaptation allows for fast action potentials in invertebrates?

giant axons

What type of impedance makes it so that Voltage would change as a function of time?


What is the expression commonly used to describe an action potential and to differentiate it from a graded synaptic potential?


What is the term for the inverse of resistance, an electrical term analogous to relative permeability?

conductance, g

There are two components of energy in a thermodynamic system. Which component is RT times the log of the concentration?

chemical energy

Both resistance and capacitance are membrane impedances. In what way is capacitance distinguished from resistance?

Voltage across capacitor changes as a function of time

The squid does not have myelin. How does the squid have fast action potentials?

Giant axons

Around 1900, Bernstein explained the action potential by a loss of the selective K+ permeability during the action potential. Although insightful, this was two bricks shy of a load. What, in fact, changes and in what direction.

Na+ permeability goes up (depending on how you read "what direction," inward flow)

Voltage can arise from a battery and (what else)?

current flowing through a resistor

How does the capacitance of the axon compare with that of the axon membrane plus the myelin?

many membrane layers, each with capacitance, add reciprocally, hence the answer is "lower with myelin"

People do not have giant axons while squids do. How do we achieve, in our axons, what squids do with that adaptation (giant axons)?


What happened to axon resistance when Cole and Curtis used the AC Wheatstone bridge as the action potential was passing?

went down

When batteries and resistances for sodium and potassium are drawn to model the Goldman equation, what special properties do the resistors have to account for the resting and action potentials?

must be variable (potentiometers)

How do Schwann cells vs oligodendrocytes differ with respect to investing axons with myelin?

Schwann, one axon, oligo a few

During propagation of the action potential, what depolarized the axon to threshold at any given location?

the action potential at one place triggers

A deliberate slight of hand had me graphing Ohm's law with the X and Y axes reversed. Thus, we talked about "conductance" which relates to what way of describing how well ions traverse a membrane channel?


Why might a middle-aged person who had recovered partially from "infantile paralysis" (polio) experience a relapse?

Post polio syndrome has sprouts of motor neurons going away (motor unit goes back to before recovery of function)

In terms of understanding resting, graded and action potentials, what does the Goldman equation (and its equivalent circuit) convey that the Nernst equation does not?

it takes into account several ions and their relative permeabilities

Applying the equilibrium assumption in deriving the Nernst equqtion (both thermodynamic systems have the same energy) we show that the electrical potential difference (across the membrane) is equal and opposite to (what?)?

chemical gradient

A current is injected into a membrane to change the membrane's voltage. How does the membrane capacitance change the membrane voltage?

it causes delay (as the membrane capacitance charges)

A deliberate slight of hand had me graphing Ohm's law with the X and Y axes reversed. In this "I-V curve" what is the slope of this line?

conductance (g)

Why do squids have giant axons? Your answer can be behavioral, it can pertain to the properties of giant axons, or it can be comparative (comparing squid with "higher" nervous systems).

so they can contract their mantle for the escape response synchronously, giant axons conduct faster, invertebrates do not have myelin

Why is salutatory conduction so much faster than conduction without myelin?

all that insulation forces the action potential to jump way ahead to the next node of Ranvier

Why is the prefix "oligo" applicable to olidodendrocytes?

they myelinate several axons in the CNS

"Capacitors in series add reciprocally." What does this say about the capacitance of myelin?

less current would leak out of the axon through the membrane capacitance where there is myelin

Why do squids have giant axons? Your answer can be behavioral, it can pertain to the properties of giant axons, or it can be comparative (comparing squid with "higher" nervous systems).

so they can contract their mantle for the escape response synchronously, giant axons conduct faster, invertebrates do not have myelin

Why is salutatory conduction so much faster than conduction without myelin?

all that insulation forces the action potential to jump way ahead to the next node of Ranvier

Why is the prefix "oligo" applicable to olidodendrocytes?

they myelinate several axons in the CNS

"Capacitors in series add reciprocally." What does this say about the capacitance of myelin?

less current would leak out of the axon through the membrane capacitance where there is myelin

By passive spread, a spike at one place depolarizes the axon ahead of it (and behind it) to threshold. Why is conduction unidirectional?

because the sodium channels behind it are inactivated, causing the absolute refractory period

Why might a middle-aged person who had recovered partially from "infantile paralysis" (polio) experience a relapse?

Post polio syndrome has sprouts of motor neurons going away (motor unit goes back to before recovery of function)

An oscilloscope presents the action potential like a graph. What are on the X and Y axes?

X time, Y voltage

Why was Golgi's technique, so exquisitely used by Ramon y Cajal, a contribution worthy of the Nobel Prize?

Among a zillion cells, one cell could be seen in its entirety

The Voltage across the membrane is ­p;RT/F times a number. R is in units of Joules/(mole x degreeKelvin) and F is in units of Coulombs/mole. Of course, we could use the term "Volts" for membrane Voltage. Alternatively use the information provided above to state what other units could be used for membrane Voltage.
Joules per Coulomb
From the 1930s to the 1950s, why did Cole and Curtis, also Hodgkin and Huxley, choose the squid instead of the frog to characterize action potential conductances?
The axon is big
I stimulate an axon with a >square wave< (an immediate step upward of voltage). Does the axon act as a high-pass filter or a low-pass filter? Justify.
Slow upsweep implies low pass (high cutoff)
"The sum of potentials, batteries and current flowing through resistors, around a loop of a circuit is zero. Also the sum of currents flowing into the junction in a circuit is zero." Whose laws are these?
In an equivalent circuit of the Goldman equation, there are batteries and resistors. What particular feature do these (in the Goldman model) resistors have?
They are variable resistors (potentiometers)
What was concluded about the properties of the axon during an action potential on the basis of Cole and Curtiss AC Wheatstone bridge experiment?
Resistance goes down
"Exponential" is the term describing Voltage as a function of time for charging or discharging a capacitor in an RC circuit. Draw this graph (for charging or discharging or both) where V is the battery's Voltage.

charging - goes up quickly then slowly, leveling off to V; discharging - goes down quickly from V then leveling

***Action potentials

Reminder: The Goldman equation looks like the Nernst equation except that it includes concentrations (in and out) plus permeabilities for all three ions - Na+, K+ and Cl-. Only one of these 9 values changes at the beginning of the action potential. Which?

permeability for Na+

Discussing the sodium channel, say something about (1) A stopper on the N-terminus of the protein, or (2) puffer fish and dinoflagellates.

(1) responsible for inactivation (2) toxin from these blocks sodium channel

What does an oscilloscope allow you to measure that a voltmeter with a needle does not?

voltage as a function of time for fast events like spikes

"The multiple layers of membrane in myelin have less capacitance than one layer of membrane would have." How would the resistance of multiple layers relate to the resistance of one layer?

multiple layers would be much higher

Immune system, say something about one of the following: (1) Active immunity, polio. (2) Passive immunity, polio. or (3) Multiple sclerosis.

1 you would get this from a vaccine or from having the disease 2 you would get it from being injected with antibodies 3 you develop autoimmunity to myelin basic protein, a self protein

In saltatory (leaping) conduction, the action potential jumps from where to where?

one node of Ranvier to the next

How is the direction that the action potential travels along the axon regulated by the refractory period of the action potential?

the refractory period keeps it from going backward (back to where it had already been)

For post-polio syndrome (worsening symptoms in middle age), according to a paper discussed in class, why is there (answer either) (1) a recovery after the initial infantile paralysis, or (2) the worsening symptoms in middle age?

spinal motor neurons sprout to connect to abandoned muscle fibers, these sprouts go away

What is the molecular mechanism for channel inactivation?

a stopper formed by amino acids near the n-terminus plugs the channel

"For passive spread of voltage along the axon, the time constant is independent of the axon radius." Then how come large invertebrate axons are faster than small ones?
The space constant varies with the square root of the radius
Oh sure, myelin ought to be a good insulator on the basis of the many layers of resistance, but what about capacitance?
Since capacitors in series add reciprocally, the many layers decrease capacitance, also making myelin a good insulator
If multiple sclerosis (MS) is caused by immunity to a protein in myelin, how come everybody does not have MS?
Autoimmunity is from the immune surveillance "seeing" a protein that is sequestered from surveillance in most people

You apply a depolarization (below threshold for triggering an action potential) at a certain place along the axon. Why would it get smaller the further away from this place that you

because current leaks out through the membrane

What is a disease of central nervous system myelin?

multiple sclerosis

What electrical properties of myelin contribute to saltatory conduction?

R & C

Permeability to what ion increases at the beginning of the action potential?


According to cable equation calculations, how does the speed of propagation relate to the radius of the axon?

square root of radius

Describe a difference between an oligodendrocyte and a Schwann cell.

myelinate several vs one axon, also CNS vs PNS

After the nerve cell integrates the excitatory and inhibitory post-synaptic potentials, which part of the cell propagates the action potential (if threshold is reached)?


Invertebrates do not have myelin. What adaptation allows for fast action potentials in invertebrates?

giant axons

If current from a depolarizing stimulus travels down the axoplasm, how come the recorded voltage would get smaller with increasing distance from the stimulus (according to the passive, "cable" properties)?

because current leaks out through membrane resistance and capacitance

What property keeps the action potential from triggering an action potential behind it as it travels down the axon?

refractory period

How does the capacitance of the multiple layers of membrane in myelin compare with the the capacitance of one layer of membrane of an axon?

capacitance in series adds inversely, so, fortunately, multiple layers have less

Why is the muscle smaller when it is innervated by a nerve damaged by polio?

because the nerve has a trophic effect on the muscle

What happens to the size of the action potential as you go along the axon?

it is all-or-none, always the same

What does "oligo-" in "oligodendroglia" refer to?

a few, each glial cell myelinates a few axons

Conductance to what ion activates late in the action potential?

The late conductance increase is for K+

If multiple sclerosis involves an immune attack on myelin basic protein, and if everybody has this protein in their myelin, how come everybody does not have MS?

rarely does autoimmunity develop

Suppose a cell's resting membrane potential is -60 mV (inside negative). Give a reasonable value for the potential if it received an inhibitory synaptic input causing a graded hyperpolarization.


Explain why propagation of the action potential is unidirectional in terms of the refractory period.

spike cannot triger a spike behind it because that membrane is still not excitable

From the cable equation, we derive properties of the space constant and the time constant. How does that tell us why invertebrates have giant axons?

space constant increases with the square root of the radius

Given that current leaks through capacitors and that membranes have high capacitance, how come myelin, with its many membrane layers does not leak a huge amount of current?

capacitors add reciprocally

For multiple sclerosis, explain autoimmunity (i.e. distinguish it from active immunity against antigens in pathogens).

the antigen is probably a myelin protein

There are cells that look like pseudomonopolar neurons in the dorsal root ganglion (just outside the spinal cord). What function do these cells serve?

sensory input

If you had one size of axon, why would the depolarization 1 mm ahead of a spike be greater with myelin than without (assuming the Schwann cell's myelin is 1 mm long).

Myelin's resistance and capacitance decreases current loss across that distance

What is the toxin from puffer fish that blocks the Na+ channel (and hence the action potential)?


What happens with botulism toxin? (Your answer can be molecular, cellular, or physiological.)

cleave synaptobrevin, block vesicle release, muscles blocked

The conclusion from Loewi's work was that there must be a substance involved. How did his classic experiment show this?

juice from chamber where vagus stimulation slowed heart slows heart in another chamber

Describe the geometry of the input to the spinal cord of the muscle stretch receptor.

cell body is in ganglion as axon goes into dorsal root

If ms (multiple sclerosis) can arise from exposure to myelin basic protein, how come everyone does not have ms?

proteins sequestered from imune surveillance except when there is autoimune disease

Why do they call neurotransmitter vesicles in the process of release "omega figures?

in EM they look like the Greek letter

Ionotropic vs. metatotropic is a way to distinguish neurotransmitter receptors. If muscarinic is metabotropic, what is the corresponding ionotropic receptor for cholinergic transmission?


What is the immediate precursor for dopamine and why is it especially useful as a treatment for patients?

l-DOPA can be given to Parkinson's patients because it crosses the blood brain barrier

What binds to adenylate cyclase to activate so that it makes cAMP out of ATP?

alpha subunit of heterotrimeric G protein

What does protein kinase A (PKA = A kinase) do to the proteins it affects?

phosphorylates them

Once it is activated, what keeps the alpha subunit of the heterotrimeric G protein from running amuck and continuing to activate the next molecule in line in the cascade?

it has GTPase activity then recombines with beta gamma

Where (specifically) is synaptobrevin and what (molecularly) does botulinum toxin do to it?

on vesicle, cleaves (prevents vesicle release)

Reuptake is the predominant mechanism to terminate norepinephrine action. By contrast, how is acetylcholine action ended?

breakdown by AChE

Why might an inhibitor of monamine oxidase (MAO) relieve depression?

potentiate "upper" action of norepinephrine by keeping it around

Why do squids have giant axons? Your answer can be behavioral, it can pertain to the properties of giant axons, or it can be comparative (comparing squid with "higher" nervous systems).

so they can contract their mantle for the escape response synchronously, giant axons conduct faster, invertebrates do not have myelin

Why is salutatory conduction so much faster than conduction without myelin?

all that insulation forces the action potential to jump way ahead to the next node of Ranvier

Why is the prefix "oligo" applicable to olidodendrocytes?

they myelinate several axons in the CNS

"Capacitors in series add reciprocally." What does this say about the capacitance of myelin?

less current would leak out of the axon through the membrane capacitance where there is myelin

By passive spread, a spike at one place depolarizes the axon ahead of it (and behind it) to threshold. Why is conduction unidirectional?

because the sodium channels behind it are inactivated, causing the absolute refractory period

Why might a middle-aged person who had recovered partially from "infantile paralysis" (polio) experience a relapse?

Post polio syndrome has sprouts of motor neurons going away (motor unit goes back to before recovery of function)

An oscilloscope presents the action potential like a graph. What are on the X and Y axes?

X time, Y voltage

Why was Golgi's technique, so exquisitely used by Ramon y Cajal, a contribution worthy of the Nobel Prize?

Among a zillion cells, one cell could be seen in its entirety

Structurally, how are Schwann cells and oligodendrocytes different?
Schwann myelinate one axon, og. Do a few (hence oligo-)
Molecularly. What does it look like when inactivation of a channel occurs?
A stopper plugs up the channel
In what way was multiple sclerosis modeled as an autoimmune disease?
A basic protein in myelin, usually sequestered from immune surveillance induces immune attack on myelin
Tetrodotoxin (from puffer fish) would kill you by what mechanism?
Blocks sodium channels and hence the action potential

"Exponential" is the term describing Voltage as a function of time for charging or discharging a capacitor in an RC circuit. Draw this graph (for charging or discharging or both) where V is the battery's Voltage.

charging - goes up quickly then slowly, leveling off to V; discharging - goes down quickly from V then leveling

In contrast with ligand-gated channels like the nicotinic receptor, how is the sodium channel of the action potential gated?

it is voltage gated, charged amino acids on alpha helix detect voltage

Why doesn't an action potential trigger an action potential behind it in the axon?

there is a refractory period caused by sodium channel inactivation

What is different about the space constant vs the time constant for the passive propagation that explains why giant axons are fast?

space constant varies with square root of radius, time constant does not

What happens to the permeabilities of the axon membrane for Na+ and K+ during the passage of the action potential?

permeability of sodium goes up then down, later the permeability for potassium goes up then down

***Synapses and Transmitters

"Hodgkin and Huxley won a Nobel Prize for telling us about Na+ and K+ conductances and how they mediated the action potential." What additional type of channel becomes critical when the action potential arrives at the axon terminal where the presynaptic membrane is located?

one for Ca2+

There is another kind of receptor for acetylcholine, other than nicotinic. Answer one of the following (1) Describe the structure of this other receptor. (2) What is it called (a pharmacological name)? or (3) What is a famous drug that blocks this other receptor?

(1) crosses membrane 7 times (2) muscarinic

We would get an EPSP with cholinergic activation of a nicotinic receptor. Conductance to what two ions is increased?

sodium and potassium

Why would it be ineffective to feed dopamine to a patient with Parkinson's disease?

it does not cross the blood brain barrier

Why doesn't cAMP keep activating PKA forever?

a phosphodiesterase turns it to AMP

Although Ramon y Cajal used Golgi's technique, and the two shared the Nobel Prize in 1906, only Ramon y Cajal's viewpoint required the existence of synaptic connections such as Nobelist Sherrington proposed. In what way did Ramon y Cajal's vs Golgi's viewpoints differ regarding this issue?

only Ramon y Cajal thought cells were separate entities that would need to signel to eachother

"There are no inhibitory neuromuscular junctions (where the spinal motor neuron makes connection to the muscle cell)." Then how is the flexor inhibited in the knee-jerk reflex?

via an inhibitory interneuron in the spinal cord's gray matter

"While you are sitting quietly in physiology lecture, unstressed, your heart is beating slower than it would automatically." Say something about (1) the transmitter. or (2) the nerve.

1 acetylcholine 2 vagus 10th cranial nerve, parasympathetic

Among the chemical intermediates in the synthesis of the neurotransmitter norepinephrine from tyrosine, there is a chemical that was eventually shown to be a neurotransmitter in its own right. What is this chemical?


"Acetylcholine's action is terminated by acetylcholinesterase." By contrast, what entirely different mechanism is predominant in the inactivation of norepinephrine?


For clostridial toxins, botulinum and tetanus toxin, answer one of the following. (1) Why would you squeeze blood out of a deep dirty puncture wound in the finger? (2) What is the name of the protein which these proteases cleave? or (3) Which specific membrane houses this protein?

1 flush out the bacteria 2 synaptobrevin=VAMP=vSNARE 3 vesicle membrane

Why doesn't the alpha subunit of the G protein keep activating adenylate cyclase forever?

when it catalyses GTP conversion to GDP plus phosphate, the alpha subunit reassociates with beta-gamma

For stretch of the extensor to mediate contraction of the extensor, there is a monosynaptic reflex arc. What needs to be added to this circuit for there to be a corresponding inhibition of the flexor?

an inhibitory interneuron

"Vagus-stuff slows the heart." Answer one of the following. (1) What major subdivision of the autonomic nervous system does vagus-stuff come from? (2) What chemical is vagus-stuff?

parasympathetic, acetylcholine

After calcium ions come into the synaptic terminal, what do they do to assist in vesicle release?

binds to synaptotagmin, a vesicle protein, fugure also shows calcium activating calmodulin

For EITHER the bacterium that causes tetanus or the bacterium that causes botulism, what is the significance of that bacterium being anaerobic?

would thrive in improperly canned goods or in deep puncture wounds

What molecule does malathion INHIBIT (leading the heart to stop)?


Chemically, what is the RELATIONSHIP of the dark pigmentation of the substantia nigra and the neurotransmitter made by the substantia nigra?

melanin and dopamine have l-DOPA as a common precursor

What is different in the gating of Ca2+ channels involved in release of synaptic vesicles vs. when IP3 interacts with the smooth endoplasmic reticulum that acts as a Ca2+-sequestering cistern?
The voltage of the action potential gates the channels for vesicle release, whereas the inositol trisphosphate channel is a ligand-gated channel
"Muscarine is an agonist for a G protein coupled receptor for acetylcholine." Name the famous agonist for the acetylcholine receptor that is a channel.
When norepinephrine is the "first messenger" activating the G protein coupled receptor, cyclic AMP has been called the "second messenger." Answer either: (1) What is the precursor of cAMP? Or (2) What is the enzyme that turned that precursor to cAMP?
ATP, adenylate cyclase

What does a kinase do to a protein?

phosphorylates it

Suppose you are stimulating the nerve to the gastrocnemius muscle. What would BoTox do to the response?

decrease it

Why might a physician give a patient a monamine oxidase inhibitor?

to relieve depression

Caffeine inhibits the enzyme that breaks down what substance?

it inhibits cAMP's PDE

What kind of post-synaptic potential (PSP) is usually a hyperpolarization?


The nicotinic receptor is a cation channel for what two ions?

K+ and Na+

What is the calcium binding protein of the synaptic vesicle?


The alpha subunit of the heterotrimeric G protein binds what molecule?

GTP (also adenylate cyclase, phospholipase C, etc)

Insecticides like malation, nerve gas, and Loewi's "vagus-stuff" would all do what to the heart?

slow it

Why might a physician give a patient l-DOPA?

to relieve Parkinson's disease, precursor of dopamine

Without a booster shot, a deep, dirty puncture wound might cause death because of the toxin of an anaerobic bacterium that cleaves synaptobrevin in inhibitory interneurons. The


What chemical is in low supply in the brains of Parkinson's patients?


What would anti-acetylcholinesterase poisoning do to heart rate?

slow or stop

The garden tomatoes were not cooked enough before being "canned" in mason jars. What would happen at the cellular or subcellular level if you eat them?

vesicles would not be released

After the alpha subunit of the heterotrimeric G protein binds GTP, what does it do to GTP?

breaks it to GDP (and P)

Although dopamine is a transmitter itself, it can be converted into what other neurotransmitter by the enzyme dopamine beta-hydroxylase?


Muscarinic receptors are for what neurotransmitter molecule?


What second messenger activates protein kinase when the beta-adrenergic receptor of a liver cell binds epinephrine?


For the monosynaptic knee-jerk reflex, what cell does the sensory neuron of the spindle's stretch receptor synapse onto?

spinal motor neuron

Conductance to what anion increases when the postsynaptic membrane hyperpolarizes?

Cl- is the biologically important anion

What is the role of the voltage gated (activated) Ca2+ channel in the presynaptic membrane?

triggers cascade for vesicle release

What would repeated overstimulation of the vagus (10th cranial nerve) do to the heart rate?

slow it or stop it

Where is the cell body of the sensory nerve mediating the knee jerk reglex?

just outside the spinal cord (dorsal root ganglion)

Why would the toxin from Clostridium botulinum be given as a cosmetic for the face by a dermatologist?

prevent facial expression that forms wrinkles

What is the pharmacological name for the type of cholinergic receptor that is a G protein coupled receptor for the parasympathetic nervous system?


What neurotransmitter does the substantia nigra make for the control of motor movements?


What would happen to levels of acetylcholine as a result of poisoning by malathion?

they would go up

What neurotransmitter is made from dopamine by the action of dopamine beta hydroxylase?


When acetylcholine binds the nicotinic receptor, conductances to what ions are increased?

K+ and Na+

The alpha subunit of the heterotrimeric G protein activates adenylate cyclase to make what out of ATP?


How is the hormone from the adrenal medulla related to the neurotransmitter from the postganglionic neuron of the sympathetic nervous system?

epinephrine (adrenalin, hormone) is made from norepinephrine (noradrenalin, neurotransmitter) with one additional enzymatic step

The nicotinic receptor is a ligand-gated channel with low cation specificity. What is the ligand?


One SNARE is on the presynaptic membrane. Where is the other?

on the vesicle

What happens to the voltage when a neurotransmitter causes K+ and Cl- channels to open?


For acetylcholine, there are ionotropic (channel) and metabotropic (G protein-coupled) receptors. What is the situation for norepinephrine?

Only metabotropic

For what kind of patient would you feed l-DOPA, and why can't you feed dopamine instead?

Parkinson's, does not cross blood brain barrier

What is it that causes the calcium channels in the axon's presynaptic terminal to open?

they are voltage gated and report the arrival of the action potential

If the extensor is activated by stretch in the knee jerk reflex, what is the mechanism by which the flexor is inhibited?

an inhibitory interneuron in the spinal cord

What does "vagus-stuff" (acetylcholine) from the parasympathetic nervous system's 10th cranial nerve do to the heart rate?

slows it

Transporters to take norepinephrine back into the synaptic terminal from the synaptic cleft constitute the main mechanism to terminate the action of this neurotransmitter. By contrast, how is acetylcholine eliminated?

acetylcholinesterase breaks it down

Given that tetanus toxin is a Clostridial toxin that cleaves synaptobrevin to inhibit vesicle release, how come muscles are overactivated in lock-jaw?

it is an inhibitory path that is blocked

How does caffeine have its stimulatory effect?

blocks cAMP phosphodiesterase

What happens with botulism toxin? (Your answer can be molecular, cellular, or physiological.)

cleave synaptobrevin, block vesicle release, muscles blocked

The conclusion from Loewi's work was that there must be a substance involved. How did his classic experiment show this?

juice from chamber where vagus stimulation slowed heart slows heart in another chamber

Describe the geometry of the input to the spinal cord of the muscle stretch receptor.

cell body is in ganglion as axon goes into dorsal root

Why do they call neurotransmitter vesicles in the process of release "omega figures?

in EM they look like the Greek letter

Ionotropic vs. metatotropic is a way to distinguish neurotransmitter receptors. If muscarinic is metabotropic, what is the corresponding ionotropic receptor for cholinergic transmission?


27. What is the immediate precursor for dopamine and why is it especially useful as a treatment for patients?

l-DOPA can be given to Parkinson's patients because it crosses the blood brain barrier

What binds to adenylate cyclase to activate so that it makes cAMP out of ATP?

alpha subunit of heterotrimeric G protein

What does protein kinase A (PKA = A kinase) do to the proteins it affects?

phosphorylates them

Once it is activated, what keeps the alpha subunit of the heterotrimeric G protein from running amuck and continuing to activate the next molecule in line in the cascade?

it has GTPase activity then recombines with beta gamma

Where (specifically) is synaptobrevin and what (molecularly) does botulinum toxin do to it?

on vesicle, cleaves (prevents vesicle release)

Reuptake is the predominant mechanism to terminate norepinephrine action. By contrast, how is acetylcholine action ended?

breakdown by AChE

By what mechanism would an injection of BoTox prevent the formation of wrinkles in your face?

Muscles that made you wrinkle your face would be paralyzed (b/c no transmitter release)

"There are no channel receptors for norepinephrine." Then how are these norepinephrine receptor proteins characterized?


How is the color of the substantia nigra related to its role in distributing a transmitter through the brain?

Melanin is a polymer of DOPA, dopamine is a product of DOPA

A cell might depolarize or hyperpolarize even when a metabotropic receptor that is not an ion channel is activated. How can this be?

Through inhibitory vs excitatory G proteins (alpha subunits)

How is it that the calcium (Ca2+) ions involved in transmitter release come into the terminal only when they're supposed to?

they come in through a voltage gated calcium channel

How is it that the flexor is inhibited in the knee-jerk reflex when all God's children know that the neuromuscular junction is only excitatory?

through an inhibitory interneuron in the gray matter of the spinal cord

A caveat to cell theory is the functional syncitium, like electrical (and cytoplasmic) continuities between adjacent myocardial (heart muscle) cells. What membrane specialization allows this intimate connection?

gap junction

A few EPSPs (excitatory postsynaptic potentials) are present simultaneously in a spinal motor neuron (Sherrington's "final common pathway" in the "integrative action of the nervous system"). Why might they not lead to an action potential in the axon hillock?

decremental conduction means they might not reach threshold at the hillock, or maybe an IPSP heads them off at the pass

The nicotinic channel is called ligand-gated to differentiate it from (what kind of channel?) involved in the action potential.

voltage gated

The synthesis of norepinephrine, an amine, from the amino acid tyrosine has long been known. Eventually, an intermediate in this biosynthesis was acknowledged as a transmitter itself. What was this molecule?


You get a deep dirty puncture wound in your finger. Why do you try to make that cut bleed?

see if you can get the bacteria (that cause tetanus and are anaerobic) out (of that anaerobic location)

"Black widow spider venom binds neurexin." And thus it affects what process?

vesicle release (it speeds up release)

There is an enzyme that makes cAMP. How is it that the enzyme is activated to make cAMP only when called upon?

when it binds GTP, the alpha subunit of the G protein interacts with adenylate cyclase

"Nicotinic" is a term applied to the postganglionic cell in the autonomic nervous system. Which part of this cell?

the postsynaptic membrane

Sherrington said that the spinal motor neuron was the final common pathway of the nervous system. How does this relate to excitation and inhibition in the spinal motor neuron vs. the muscle cell?
b/c there is only excitation on the end plate, the neuron is the last chance to integrate IPSPs and EPSPs
"Botulinum and tetanus toxins cleave synaptobrevin." In terms of nerve function, why would they kill you?
Prevent vesicle release
What would be the cause of death if you were poisoned by malathion, an inhibitor of acetylcholinesterase?
Heart would stop
At one time, the precursor of norepinephrine was considered to be just that, a step in the pathway to norepinephrine synthesis. Now it is considered an important transmitter. Answer either (1) What is it called? (2) Where does it come from in the brain? Or (3) Its deficiency is the cause of what disorder?
1 dopamine 2 substantia nigra 3 Parkinsons
"The alpha subunit stimulates adenylate cyclase." Answer either (1)The alpha subunit of what heterotrimeric molecule? (2) What stimulated this heterotrimeric molecule? Or (3) What does the adenylate cyclase make when it is stimulated?
1 G protein 2 G protein coupled receopto 3 cAMP
Caffeine: Answer either (1) What does it do chemically? Or (2) What neurotransmitters action is potentiated by its action?
1 block the PDE that inactivates cAMP 2 NE

Choline-O-acetyltransferase: Answer either (1) What is it used for? or (2) Where is it located (specific cell compartment)?

make acetylcholine, in synaptic terminal


A nerve comes out from the central nervous system, and this nerve's output slows the heart. Where (anatomically) does this nerve come out from?

brain (the cranio part of the craniosacral system)

In the thoraco-lumbar system, in the sympathetic chain of ganglia, postganglionic cells use nicotinic receptors to what neurotransmitter?


The autonomic nervous system would influence the heart rate (at the SA=sinoatrial node) with 2 types of receptors, beta-1 receptors plus (what other receptor)?


I remind you that the sympathetic nervous system mediates vasoconstriction in peripheral vascular beds. Now your turn. What part of the autonomic nervous system meciates vasodilation (hyperemia) in muscle?


Why doesn't a molecule of cGMP keep mediating smooth muscle relaxation (in arterioles in the corpus cavernosum) forever?

a phosphodiesterase converts cGMP to GMP

Are channels (ionotropic receptors), G protein coupled receptors (metabotropic receptors) or both used in the parasympathetic nervous system?

both, nicotinic at ganglion, muscarinic at effector

31. Which part of the autonomic nervous system utilizes a chain of connected ganglia near the spinal cord?


32. An eye care professional (for ophthalmoscope examination) [or a "beautiful woman", for cosmetic purposes] puts atropine in the eye. Answer either (1) What component of the nervous system is affected? Or (2) What is the pharmacological name of the receptor that is blocked?


33. Before they knew the chemical identity (NO = nitric oxide) they used an operational name (EDRF = endothelial derived relaxation factor). Answer either (1) What is housed in endothelial cells to make NO? or (2) What is it that was made to relax by this factor?

eNOS (endothelial Nitric Oxide Synthase), smooth muscle in arterioled to the corpus cavernosum

What is the interesting parallel in the actions of Viagra and caffeine?
They both inhibit a phosphodiesterase, Viagra inhibits cGMP breakdown and caffeine inhibits cAMP breakdown
17. What difference, if any, is there between the neurotransmitter used to activate beta-1 adrenergic receptors vs. beta-2 adrenergic receptors?
No difference, norepinephrine for both
What chemical does Viagra inhibit?

the phosphodiesterase for cGMP

What gas mediates arteriole dilation by the parasympathetic nervous system?

NO (nitric oxide)

A nasal decongestant spray would contain an agonist for what naturally ocurring neurotransmitter?


The anatomical term "cranio-sacral" refers to what functional unit?

parasympathetic nervous system

For what condition was propranalol, a "beta blocker," given?

high blood pressure

The anatomical term "thoraco-lumbar" refers to what functional unit?


An asthma spray would contain an agonist for what naturally ocurring neurotransmitter?


Where are nicotinic receptors used in the autonomic nervous system?


In addition to cranial nerves, what other nerves make up the parasympathetic nervous system?


What is the corpus cavernosum?

erectile tissue

Muscarinic receptors are for what neurotransmitter molecule?


What would sympathetic activation do to the blood flow in muscle?

increase it

Identify one of the two parts of the central nervous system where the parasympathetic output originates. Be specific.

Brain (for cranial nerves) and sacral part of the spinal cord

Propranalol is a btea-1 blocker, and it is given to patients to prevent the action of what neurotransmitter at what site?

norepinephrine in heart

A patient comes in and his heart is stopping because of exposure to malathion. What do you give him?


Why would atropine be a useful ingredient in medication for diarrhea with cramping?

inhibits parasympathetic meciated activation of gastrointestinal motility

Why are treatments like nitroglycerine contraindicated for men who are on drugs for erectile dysfunction?

An unsafe drop in blood pressure would result from too much smooth muscle relaxation

"The parasympathetic nervous system dilates arterioles in the corpus cavernosum, mediating erection." Give either of the reasons that this statement is not the whole truth according to more modern research.

(1) actually, the parasympathetic nervous system inhibits the sympathetic for this. Also (2) a non-cholinergic non-adrenergic system is of paramount importance.

"Nicotinic" applies to which place (i.e. preganglionic axon terminal, postganglionic synaptic receptors, postganglionic axon terminal, effector receptors)? Justify.

The acetylcholine receptor on the postganglionic cell body

What specific kind of receptor does atropine block?

Cholinergic muscarinic

Where does nicotine have its effect?

on nicotinic acetylcholine receptors most notably in autonomic ganglia

What is the significance of the endothelial cells that line blood vessels in mediating erection?

endothelial derived relaxation factor (EDRF= nitric oxide[NO]) is made there

In which part of the autonomic nervous system is the ganglion near the neuroeffector junction?


What specific type of receptor mediates the sympathetic nervous system's effects on the heart?


Hyperemia, increased blood flow in skeletal muscle, is mediated by what functional subdivision of the nervous system?


How does a nasal decongestant spray like phenylephrine work?

constricts arterioles

Why would a beta blocker like propranalol be given for high blood pressure?

would block beta adrenergic receptors in heart, decrease heart rate and force or volume

How does Viagra work?

inhibit PDE to break down cGMP

What kind of muscle does the autonomic nervous system connect to?


Usually your eye care professional will administer something to dilate the pupils. What type of receptor for what neurotransmitter is blocked?

muscarinic for acetylcholine

For which component of the autonomic nervous system is the ganglion closer to the central nervous system?


Explain how vasoconstriction (or the opposite) applies to how a decongestant unclogs a stuffed nose.

An alpha agonist like phenylephrine constricts engorged vascular bed

"Control of arteriole smooth muscle involves "unique" innervation, sympathetic only. Except for (what?).

arterioles to the corpus cavernosum

"This and other erectile dysfunction medications should not be taken if you are taking nitrates for chest pain." Why not?

the combined actions, all causing relaxation of arteriole smooth muscle, would cause an unsafe drop in blood pressure

In one figure, "autonomic ganglia" were shown in a chain near the spinal cord. Which subdivision of the autonomic nervous system is this?


What transmitter receptor would be affected by a spray to unstuff a a stuffed nose, and would you use an agonist or an antagonist?

phenylephrine is an agonist for alpha adrenergic receptors

Why does the inner layer of the blood vessel (the endothelium) come up in an explanation of erection?
Endothelial NOS makes NO
"The autonomic nervous system is a motor system." Thus the CNS (central nervous system) location of the cell body of origin (not the ganglion) is in the gray matter of the spinal cord and also (finish this sentence).
The brain
In the somatic motor system, connecting to striated muscle, we refer to the "neuromuscular junction." For the autonomic nervous system, we are more non-committal with the term "neuroeffector junction<"instead. Why?
b/c it could also be glands
For nicotine, answer either (1) Where (anatomically) does it affect the autonomic nervous system? Or (2) What neurotransmitter is involved?
1 the ganglia 2 acetylcholine
Via beta-1-adrenergic receptors, the sympathetic nervous system increases the contractility of heart muscle and (in what other way does it affect the heart?).
increase rate
Why would people have used a muscarinic receptor blocker as a cosmetic?
Dilated pupils are appealing


What is the ATP binding protein in a striated muscle cell?


What muscle protein does Ca 2+ bind to in mediating muscle contraction?


What disease (or, alternatively answer what ionic manipulation) would make the excitatory motor end plate potential insufficient to fire an action potential along the sarcolemma?

myasthenia gravis (or lower extracellular calcium

People who do not have one familial type of Amyotropic Lateral Sclerosis have an enzyme that does what? (an enzyme that ALS victims do not have).

copper zink superoxide dismutase would reduce oxygen free radicals

What is it called when a lot of twitches come in such rapid succession that they produce a steady muscle contraction?


Where does muscle lactic acid get turned back into glucose?


What effect would the conversion of ATP to ADP plus inorganic phosphate have upon creatine?

turn it to creatine phosphate

In terms of banding pattern, what is the place where there is myosin but no actin?

H band

Actin, myosin, tropomyosin, troponin. Name another important muscle protein of each sarcomere of a striated muscle fiber.

titin dystrophin

Why, in terms of actin and myosin, is the tension a muscle can achieve lower for a muscle at 160% of its resting length than for a muscle at its "ideal" resting length?

less overlap of actin and myosin

After inorganic phosphate is released from the binding pocket and before ATP binds to the myosin head... Answer one of the following (1) What is released from the binding site? of (2) What happens upon this release?

ADP power stroke

"Fewer muscle cells are innervated by one motor neuron in extraocular eye muscles than for the calf muscle?" What is this assembly of muscle cells innervated by one neuron called?

a motor unit

What drug (or, alternatively, answer what this drug does) would be given to a patient with myasthenia gravis?

neostigmine, inhibit acetylcholinesterase

What is the poison that blocks nicotinic receptors at the neuromuscular junction?


What enzyme functions in your spinal motorneuron but is not functioning in people with one familial type of ALS (Lou Gehrig's disease)?


Nicotinic receptor, sarcoplasmic reticulum calcium channel, voltage-gated sodium channel. One channel in the muscle cell is missing from this list. Answer either (1) for what ion? or (2) in what specific location?

calcium (2) T-tubules

Name a pigment that makes turkey drumstick meat dark (in comparison with white meat).

hemoglobin, myoglobin, cytochrome

Plasma glucose, plasma free fatty acids, muscle triglyceride. What huge source of muscle energy is missing from that list?

muscle glycogen

Activation of end plates on nuclear chain fibers... Answer either (1) comes out by what specific nerve cell type? or (2) ia useful for what reason?

(1) gamma motor neuron (2) preset stretch of stretch receptor

Action potentials in smooth muscle cells lead to an increase in cytoplasmic calcium ions. Answer either (1) Where did this calcium come from? or (2) What is the calcium binding protein?

(1) from outside the cell (2) calmodulin

A muscle protein is deficient in Duchenne muscular dystrophy. Describe the location or function of this protein.

near the membrane, cytoskeleton or structure

How do you explain the shape of the length - tension curve for striated muscle?

weaker when the overlap of actin and myosin is too low or too high

"Power stroke causes filaments to slide; ADP is released." Answer either (1) What was released just before the ADP was released? (2) ADP was released from what molecule? Or (3) What comes in to fill the empty pocket where the ADP had been?

phosphate, myosin, ATP

If muscle is not "supposed to" contract (i.e. it has not been activated by an action potential), what molecule keeps myosin from binding to actin?


Say something (else) about the properties of the type of muscle fiber that is sometimes called fast twitch.

white meat, anaerobic, strong but not enduring

The action potential is carried on the sarcolemma by sodium channels. For either (1) the T(transverse)-tubules or (2) the sarcoplasmic reticulum, what channels are important?

calcium (for both)

You write a proposal to SLU's animal care committee for surgical research on mice. You propose to anesthetize animals with a nicotinic receptor antagonist and you justify this choice because the animal is unresponsive to a painful stimulus. The committee flatly rejects your proposal. Why?

curare or the like would paralyze the animal, not prevent pain

In addition to ATP interconversion with ADP plus inorganic phosphate, what other substance that interconverts between phosphorylated vs. non-phosphorylated forms is present as a small energy store in muscle?

creatine - creatine phosphate (phosphocreatine)

In muscle, hemoglobin would offload oxygen to myoglobin. Explain in terms of the oxyhemoglobin dissociation curve.

since the myosin curve is to the left of the hemoglobin curve, it means that myoglobin has a higher affinity for oxygen

What does Ca2+-calmodulin activate to make smooth muscle contract?

myosin light chain kinase (MLCK)

In the middle of the sarcomere's A band is a lighter area (H band). Why is it lighter than the rest of the A band.
there is myosin but no actin
What important protein of each sarcomere is missing from the following list? Titin, myosin, tropomyosin, actin.
In heavy exercise, and heavy exercise can only be maintained for a short duration, glucose, delivered from blood plasma, and glycogen, resident in muscle cells, are the predominant energy sources. What is the predominant energy source (and where does it come from?) for light exercise for long duration?
free fatty acids from plasma
Because cardiac output limits oxygen delivery to muscle... (Say something about how the utilization of glucose by muscle is altered.)
this is why God gave humans anaerobic glycolysis
"Nuclear chain fibers contribute to the reflex." Answer either (1) How? Or (2) Via what type of neuron from the spinal cord?
by presetting the stretch on stretch receptors, gamma fibers
"The axon ends in the axon terminal where the neuron makes a synapse onto the next cell." Describe an exception to this geometry for an autonomic neuron affecting smooth muscle.
instead of an axon terminal, there are numerous varicosities

Shortage of what chemical leads to rigor mortis?


What is an intrafusal motor fiber?

presets stretch on spindle's stretch receptor

What does a kinase do to a protein?

phosphorylates it

Suppose you are stimulating the nerve to the gastrocnemius muscle. What would BoTox do to the response?

decrease it

When does a spinal motor neuron cause a hyperpolarization at the end plate of a striated muscle cell?


In the middle of the dark A band is a lighter H zone. Why is it lighter?

because there is myosin but no actin

What ion, critical to muscle contraction, binds troponin, pulling tropomyosin myosin's binding site on actin?


What is the ATP binding protein in muscle?


During exercise, what does the conversion of phosphocreatine to creatine achieve?

makes ATP

During anaerobic metabolism in muscle, what is pyruvic acid converted to?

lactic acid

The sarcoplasmic reticulum calcium release channel is closely related with what channel on the transverse tubule?

a different calcium channel

Several diagrams in your book referred to skeletal muscle fibers as "extrafusal muscle fibers." Why?

to distinguish them from intrafusal in muscle spindle

What happens to the relationship of actin and myosin when ATP binds?

they unbind

While exploring the Amazon, you are shot with a blow-gun dart of curare. What would that do to you?


For the monosynaptic knee-jerk reflex, what cell does the sensory neuron of the spindle's stretch receptor synapse onto?

spinal motor neuron

Why is Duchenne muscular dystrophy more common in boys than in girls?

because the mutation is X-linked

What does "striated" mean in the context of striated muscle, and why was the fact that muscle is striated important in developing the sliding filament theory?

striped, helped Huxleys infer actin & myosin properties

Why would it be easier halfway up a chin-up than starting from a position of fully extended arms?

optimal overlap of actin and myosin as opposed to too little overlap

Heart muscle does not follow the length-tension relationship of skeletal muscle. Why is this important?

Fuller ventricle is capable of generating more force of contraction

What treatment would alleviate some of the muscle weakness from autoimmunity to the nicotinic channel?

anti-acetylcholinesterase like neostigmine

Lowering extracellular Ca2+, Katz did his Nobel Prize winning work as he converted the end plate potential to miniature end plate potentials elicited by "quanta." What is the physical appearance of the quantum he witnessed physiologically?


The channel carrying the action potential in the T (transverse) tubule is closely linked to what important component in muscle contraction?

sarcoplasmic reticulum (the Ca2+ channel)

What prevents the myosin head from binding actin in striated muscle when a contraction is not called for?


How would motor units differ in the extraocular muscles (responsible for eye movements) vs. calf (gastrocnemius) muscle?

fewer muscle cells per neuron in muscles for finer movement

Which cell is damaged in ALS (amyotropic lateral sclerosis, Lou Gehrig's disease)?

spinal motor neuron

In smooth muscle, what can phosphorylated myosin light chain do that the unphosphorylated protein cannot?

bind actin

Gamma fibers preset the stretch receptor by causing what specific type of fiber to contract?

intrafusal (or nuclear chain)

What is created from glycogen by glycogenolysis?

glucose (or glucose 6-phosphate)

What type of cell uses phosphocreatine (creatine phosphate)?

striated muscle

If there is lactic acid formation, oxygen debt, and creation of only a few ATPs per glucose molecule, what is this type of metabolism called?

anaerobic glycolysis

Varicosities on autonomic nerves are used to control what kind of muscle?

smooth muscle

Without Ca2+ what does tropomyosin block?

Binding sites on actin for myosin

What transmitter and transmitter receptor are used at the motor end plate?

Acetylcholine nicotinic

Why would curare, by itself, be a poor choice for anesthetizing a patient for surgery?

It is a paralytic, not an anesthetic

In what way does a graph of tension as a function of time look different for complete vs. incomplete tetanus?

Bumpy for incomplete

In what way does smooth muscle's myosin light chain kinase (MLCK) substitute for striated muscle's troponin-tropomyosin complex?

Phosphorylation of myosin allows cross-bridges

Here is a partial list of the proteins of striated muscle: actin, myosin, troponin, tropomyosin. Name another.

titin, dystrophin, myoglobin

What happens specifically when either phosphate or ADP (you pick one) comes off the myosin?

myosin binds to actin and power stroke is taken

One sarcomere goes from the z-line (z-disc) to (where)?

the next z line

How would the H zone look in the biceps at the bottom of a chin-up vs. at the top?

H big at bottom, small at top

T-tubules (transverse tubules) are best known for their channels for which ion?


If you are not active at the time, after a meal, "in times of plenty," glucose is imported into muscle and converted into what?


What would happen to the end plate potential elicited by one spike in the motor neuron if the extracellular concentration of Ca2+ in the vicinity of the neuromuscular junction were reduced?

become smaller, become ), 1 or several miniature potentials

By what mechanism does neostigmine help a patient with myasthenia gravis?

increase acetylcholine to better stimulate what is left of the nicotinic receptors

What is the limiting factor that requires the body's muscles to go to anaerobic glycolysis for extreme exertion?

heart's ability to deliver O2

What is the X-axis (abscissa) for the oxyhemoglobin dissociation curve, the graph that shows that myoglobin has a higher affinity for oxygen than hemoglobin?

partial pressure of O2 in mm Hg

What is a nuclear chain fiber used for?

intrafusal muscle to preset stretch receptor

Why can't myosin bind to actin unless it's supposed to?

tropomyosin blocks the sites on actin for myosin binding

Which muscle protein changes configuration, power stroke and back stroke, for muscle contraction?


Put in order from large to small three alternative, anatomical, words for muscle cell, the subcomponents that make up the cell, and the muscle proteins that make up these subcomponents.

cell=fiber, myofibril, filament=protein

How does the conversion of ATP to ADP affect creatine?

creatine becomes creatine phosphate

What is the function of gamma fibers and their connection to nuclear chain fibers?

preset stretch for stretch receptor

Under the influence of Ca2+-calmodulin, what protein in smooth muscle gets dephosphorylated?

myosin light chain kinase

Give one way the neuromuscular junction is distinguished from the typical synapse in the nervous system.

larger, only excitatory

In terms of the muscle proteins, why is the muscle weaker when it is full length or stretched?

less actin myosin overlap

In terms of muscle proteins, why does the length of the H (helle) zone vary with muscle length?

myosin without overlap with actin

Where is the lactic acid that is built up in muscle taken care of?


Ca2+ channels in the t- (transverse-) tubules are in contact with Ca2+ channels in what subcellular structure.

sarcoplasmic reticulum

What famous drug paralyzes skeletal muscle by blocking the muscle membrane receptor?


What is the cause of the disease of muscle weakness in which nicotinic receptors are lacking?

autoimunity to nicotinic

What enzyme is deficient in familial cases of Lou Gehrig's disease?

Super Oxide Dismutase

How does the oxyhemoglobin dissociation curve explain the offloading of oxygen when blood arrives at muscle?

myoglobin's curve is to the left

Striated muscle's tension (strength) depends on its length. Out of A-band, I-band, and H-zone, which ones change size (as a function of muscle length) and which do not?

A stays the same, I and H would change

Why did they call one muscle protein "dystrophin?"

before they knew anything about function, they identified it as deficient in muscular dystrophy

Calcium ions would indirectly regulate whether ATP is used in muscle. Why wouldn't ATP replace ADP if calcium had not done what it does?

myosin needs to be able to bind actin for that ATP cycle to be able to run

What happens to tropomyosin to allow (or not) muscle contraction?

it exposes (or blocks) binding sites for myosin on the actin

Sir Bernard Katz won his Nobel Prize for demonstrating the quantal nature of transmission at the neuromuscular junction. What happened when he lowered the extracellular Ca2+?

fewer (for instance 0, 1, or 2) vesicles (his quanta) were released

From the depolarization at the nicotinic receptors of the motor end plate, an action potential (using activated Na+ channels) moves down the sarcolemma (muscle cell membrane). That triggers what other channels? (Your answer could state what ion or what cellular component.)

calcium in both t-(transverse)-tubules and sarcoplasmic reticulum

In human surgery (and in animal research), you cannot tolerate muscle movement. Why do you need to be particularly careful about using muscle relaxants?

you need to be certain the patient (or animal) is sufficently anesthetized because paralysis would prevent any communication of distress

What is the significance of myoglobin's curve being to the left of hemoglobin's curve (on the oxyhemoglobin dissociation graph)?

hemoglobin would offload oxygen to muscle

In contrast with the type of cell an alpha motor neuron innervates, what does the gamma neuron connect to?

intrafusal muscle in the muscle spindle

Intracellular Ca2+ is exquisitely orchestrated. In contrast with the calcium binding protein of striated muscle, what is the calcium binding protein of smooth muscle?


Striated muscle has an optimum length, and it's strength (tension) drops off when it is longer or shorter. In what way is the ventricular myocardial muscle strikingly different?

The fuller (more stretched) the ventricle, the more forceful the contraction

Why is a corpse at a crime scene referred to as a "stiff?"

When ATP runs out, actin stays bound to myosin

Why would neostigmine ameliorate the condition of myasthenia gravis?

Shortage of nicotinic channels is somewhat overcome if there is more ACh

What cell is deficient in Lou Gehrig's disease (ALS=amyotropic lateral sclerosis)?

Spinal motor neuron

What are varicosities with respect to control of smooth muscle?

NE is released not so much by synaptic terminals but by many swellings along the axon

A whole lot of sarcomeres stacked end to end form (what is the name of?) a substructure within the striated muscle cell?

a myofibril

One approach to genetics has been to "identify" the protein product of a gene on the basis of a disease that affects that gene. Tell about the protein defect in Duchenne muscular dystrophy.

dystrophin links cytoskeleton with extracellular matrix across membrane

Bernard Katz won a Nobel prize demonstrating that the "quantum" of neurotransmission at the motor end plate is the vesicle. He made it so that one action potential (in the spinal motor neuron) would release 0, 1, 2, or 3 vesicles. How did he achieve this reduction?

by reducint the calcium ions that come in to mediate vesicle release

For myasthenia gravis, answer either (1) What is missing? (2) Why? Or (3) What helps to relieve the symptoms?

nicotinic acetylcholine receptors at the motor end plate because of an autoimmune attack, use an acetylcholinesterase inhibitor like neostigmine

For curare, answer either (1) Where does it act? Or (2) What is it's effect?

neuromuscular junction, block nicotinic receptor

For ALS (Amyotropic Lateral Sclerosis, Lou Gehrig's disease), answer either (1) What is the first enzyme defect isolated? or (2) What chromosome is the disease on?

SOD, 21

Give an explanation, from developmental biology, of why there are many nuclei in a skeletal muscle fiber.

Myoblasts fuse to make muscle fiber
Why would a body builder want to exercise before a show?
Hyperemia would make muscles look larger
If we were to compare fully extended vs. contracted striated muscle in histology, how, if at all, would the I-band look different?
Shorter in contracted
In muscle contraction, which needs to bind to muscle protein first, calcium ions or ATP? Justify your answer.
Calcium. ATP cannot replace ADP until myosin can see the binding sites on actin
"The problem is that the action potential is on the muscle cell membrane quite some distance from most of the sarcomeres." How is that problem solved?
t-tubules get action potential around
"Action potentials are all or none. In contrast, muscle twitches" (finish this sentence and mention what happens when there are a whole lot of twitches).
Twitches can have summation and if enough twitches add, there is tetanus
"The turkey leg has dark meat, and the reason it looks dark is" finish this sentence.
Hemoglobin, myoglobin, cytochromes

In addition to muscle glycogen and blood glucose, what material from where supplies calories for muscle?
Fat in muscle, fatty acids in blood
Describe how the blood stream succeeds in delivering oxygen to muscle by describing how that looks on the oxyhemoglobin dissociation curve.
Since mgb is to the left of hgb, hgb offloads oxygen to mgb
In what way does the source of calcium ions differ between smooth muscle and striated muscle?
From extracellular smooth, SR striated
When activated, what effect does myosin light chain kinase (MLCK) have on contraction of smooth muscle.
Phosphorylates myosin allowing cross bridges and myson and actin to slide

In anaerobic glycolysis, there is a need to regenerate NAD+. What process makes this happen?

formation of lactic acid

"The nuclear chain fiber is an intrafusal motor fiber." Answer either (1) Where is it? Or (2) What function does it serve?

in the muscle spindle, preset stretch on stretch receptor

In what way are varicosities important in the function of smooth muscle?

instead of nerve terminals, varicosities are sites of norepinephrine release


Glucose monomers can be linked either as starch or glycogen or differently, and people cannot digest this different polysaccharide. Answer either (1) What is this molecule called? or (2) Why can cattle and termites digest this molecule (while we cannot)?

cellulose, they have mutualistic microbial symbiotes

Compared with a saturated fatty acid, what must be missing from a carbon in a fatty acid that has a double bond to its neighboring carbon?


A hormone mediates the effect of the sympathetic nervous system to act on the liver cell for the release of glucose. Answer either (1) What hormone? or (2) If an increase in cAMP results from stimulation by this hormone, what kind of receptor to the hormone is used?

epinephrine (adrenalin), beta-adrenergic

The insulin receptor is an enzyme. What reaction does it catalyze?

a receptor tyrosine kinase adds a phosphate to the amino acid tyrosine

In digestion, monomers are broken out of polymers by hydrolysis. What is it called when monomers are put together?

dehydration synthesis

Regarding the carbohydrate in milk, answer either (1) What is that sugar called? or (2) Why is it thought that adult Caucasians of Northern European origin are more likely to be able to digest this sugar than adults of other ethnic origins?

(1) lactose (2) they evolved in the company of dairy husbandry

Glycerol is a 3 carbon chain with an alcohol (-OH) on each carbon. Each fatty acid that gets linked to glycerol has an acid (-COOH) group. How were the alcohols and acids altered to make the ester bond?

water was taken out

"Salts of Cholesterol" Answer either (1) What is the function? or (2) Where are they made in your body?

(1) emulsify fats (2) liver

Urea is manufactured in your body from carbon dioxide plus what waste?


Once glucose is split in half, there are two duplicate pathways leading to two respective pyruvic acids. Each limb generates 2 ATPs. Why, then, does glycolysis, as a whole, generate only 2 ATPs?

two ATPs were used up in glycolysis

Regenerating NAD (from NADH plus H+) is essential for what process?

anaerobic glycolysis

Adenylate cyclase converts (what?) into cAMP?


A hydrogen is split into H+ plus what?

an electron

Three fatty acids bound to glycerol by a dehydration synthesis (condensation reaction). What is this molecule?

fat = triglyceride

Salts of cholesterol - answer either (1) Why are they useful in digestion? Or (2) Where do they come from?

emulsify fats, liver

Why is the liver essential in getting rid of wastes generated by getting energy from amino acids?

that is where the reaction to make urea takes place

After glucose is chopped into two pieces, on the way to making two molecules of pyruvate, two ATPs are generated on each of the two reactions. Why is the value given for the number of ATPs made by glycolysis less than this value (this value equals 2 x 2 = 4)?

Two ATPs must be used

Name something other than pyruvic acid that can feed in to make acetyl CoA at the entrance to the Kreb's cycle.

amino acids, fatty acids, ketone bodies

"In other words, H is split into H+ plus (what?)".

an electron

Upon binding insulin, the insulin receptor, an enzyme, forms a dimer. Then what does this enzyme do?

it phosphorylates itself, it phosphorylates another protein

"Disulfide bonds hold together some places along the length of a protein." What level of organization is this?
Glucose is taken up into a liver cell. During an ordinary day in your life, when does this happen?
After meals

What does the dehydration synthesis have to do with the comparison with monosaccharides and glycogen?
Puts units together in macromolecule
I rationalized that you might call a releasing hormone from the hypothalamus to the pituitary (through the portal system) a "peptide." Why peptide rather than protein?
Very short
Urea, answer one: (1) Referring to energy metabolism, why do we make this? Or (2) What are the precursors?
1 nitrogenous waste when a.a.used as calories 2 NH3 (ammonia) and carbon dioxide
"Fatty acids are chopped down two carbons at a time." Where, specifically, does this 2-carbon segment go to generate ATP.
Right to acetyl co-A in Krebs
When the insulin receptor dimerizes upon activation by insulin, answer either (1) What is the result of this enzyme's activity? (2) What molecule does this enzyme act on? Or (3) Where did the phosphate come from?
1 phosphate gets added to tyrosine 2 the insulin receptor itself 3 ATP

For cellulose, answer either (1) Describe it's structure. (2) How is it dealt with in your digestive system? Or (3) How do cattle and termites digest it?

a polymer of glucose with bonds that make it indigestible for humans, hence fiber, bulk. microbes in the guts of cattle and termites help them utilize this source of glucose

"The beta-adrenergic receptor crosses the membrane 7 times." Give (and justify) one level of protein structure (related to primary to quaternary) for this G protein coupled receptor.

primary (sequence of amino acids) of course, secondary - alpha helices

Epinephrine activates a beta-adrenergic receptor on the liver cell with the end point being the release of glucose to the blood stream. Give me one of the next two molecules downstream in this signal transduction cascade.

G protein, adenylate cyclase

"Protons run through a membrane molecule like water through a water wheel to generate ATP." Answer either (1) What was the energy source to create that proton gradient? Or (2) Where is this taking place in the cell?

electron transport in the inner mitochondrial membrane

For glucose transport across the membrane, answer either (1) How does insulin cause an increase [in glucose transport] for facilitated diffusion? Or (2) Why, for a different type of transporter, is energy (in the form of ATP) required?

more transporters (GLUT-4) are deployed to the membrane, for the sodium glucose cotransporter, sodium then needs to be pumped

What does a kinase do to a protein?

phosphorylates it

How does glucose get into a cell?

you need a membrane protein for diffusion

What is the activity of the insulin receptor enzyme?

tyrosine kinase

What is the polymer of glucose that is so important in muscle and liver metabolism?


How is it that facilitated diffusion of glucose is increased by insulin?

more GLUT4 transporters deployed to membrane

The opposite of dehydration synthesis (condensation reaction) happens in digestion. What is this called?


About how many ATPs do you get from full aerobic metabolism of one glucose molecule?


During anaerobic metabolism in muscle, what is pyruvic acid converted to?

lactic acid

What is the function of salts of cholesterol made by the liver and secreted into the small intestine?

emulsify fats

When I remind you that the insulin receptor is a tyrosine kinase, where is tyrosine and what happens to it?

on intracellular side of enzyme, tyrosine (amino acid) becomes phosphorylated

What second messenger activates protein kinase when the beta-adrenergic receptor of a liver cell binds epinephrine?


In your body, what becomes of the amine of an amino acid if you use that amino acid for calories?

becomes ammonia that gets converted to urea

In your digestion, macromolecules are hydrolyzed. What is the name of the opposite reaction that had been used to string together monomers into a polymer?

dehydration synthesis

Arachidonic acid has 4 double bonds. What is the term for such a molecule?

polyunsaturated fatty acid

While fasting, what does the liver do with the glycogen it stores?

breaks it to glucose and sends that to the blood stream

How many pyruvic acids do you get from one glucose?


If a fatty acid were 14 carbons long, how many acetyl co-A's would be delivered to the Krebs cycle if it were chopped down completely in catabolism?


Epinephrine, acting on the beta adrenergic receptor, causes what to happen to glycogen in the liver?

breakdown to glucose and release to bloodstream

In addition to facilitated diffusion, there is a transport mechanism for glucose requiring energy delivery from ATP. To what molecule does ATP deliver its energy?

the sodium pump

In the biosynthesis of fat, to attach a fatty acid to glycerol via an ester bond, what molecule must be removed?


Fatty acids are "chopped down" two carbons at a time to feed into metabolism. Where do these two carbon components feed in (biochemically)?

acetate (acetyl CoA)

The need to regenerate NAD+ from NADH causes the formation of what from pyruvic acid?

lactic acid

What molecules are generated from the complete aerobic cellular respiration of glucose (in addition to energy)?

H2O and CO2

What are the salts of cholesterol of bile used for?

emulsify fats in digestion

Chemically, how is a polyunsaturated fatty acid different from a fully saturated fatty acid?

Double C=C bonds

What do we have to get rid of if we use amino acids for energy?

Nitrogenous waste

The hormone epinephrine (adrenalin) is sometimes considered the "first messenger" to signal the liver of the need to release glucose. Within the liver cell, what has been called the "second messenger" in this signal transduction cascade?


What is urea made from and where does the body make it?

NH3 and CO2 in the liver

Describe the structure of hemoglobin in terms of protein subunits and the units where iron is located.

2 alpha and 2 beta protein chains each with a heme group

How is it that a liver secretion can emulsify fats to aid in digestion?

salts of cholesterol would have hydrophilic and hydrophobic sides

On the way to the Kreb's cycle, fatty acids are chopped down two carbons at a time to make what?

acetic acid or acetyl coA

"H is split to a proton and an electron." To achieve what?

to drive proton pump then capture energy of proton pump to make ATP

How can a cell's ability to take up glucose be so different with vs without insulin?

insulin causes the membrane deployment of transporters

What molecule donated the phosphate when insulin prompted the insulin receptor dimer to phosphorylate itself?


What would a beta adrenergic receptor on a liver cell mediate?


For one type of glucose transporter, not the facilitated diffusion, energy is required. How is that energy delivered?

when glucose is cotransported with Na+, the sodium pump

Carbon dioxide plus (what?) are converted into urea in the liver.

ammonia (NH3)

Polymers (macromolecules) are constructed from their building blocks by (what process)? (the opposite of how they are broken down in digestion)

dehydration synthesis (as opposed to hydrolysis)

"Salts of cholesterol" - relate to digestion. (Your answer could refer to an organ or a process.)

from the liver into the duodenum (small intestine) to emulsify fat

Sutherland's Nobel Prize winning work had cAMP as the "second messenger." For the "first messenger," what is the type of receptor on the surface of the cell?

beta adrenergic

How does fat feed into metabolism to render ATP? (An answer for either type of components that make up a fat will be OK.)

glycerol gets converted to the precursor of pyruvic acid. Fatty acids get chopped down 2 carbons at a time to become acetyl CoA

"You're not going to get carbon dioxide from anaerobic glycolysis" because it is made in what specific step?

Krebs cycle

Why would you ultimately need energy (ATP) for one type (which type?) of glucose transporter?

the one that uses sodium ions running down their concentration gradient - those ions need to get pumped back out

What use is made of protons (H+, hydrogen ions) running back down their concentration gradient (after they had been pumped up that gradient)?

This is the "water turbine" to generate ATP

"Tyrosine kinase" - where did the phosphate come from?

ATP donates the phosphate there (and pretty much everywhere)

Amino acids can be used for catabolic energy. Where do they feed into the metabolic mill?

Into pyruvic acid just before acetyl co-A

What would a beta adrenergic receptor on a liver cell mediate?

Via cAMP, increase conversion of glycogen to glucose

What does the dehydration synthesis have to do with the comparison with monosaccharides and glycogen?
Puts units together in macromolecule
I rationalized that you might call a releasing hormone from the hypothalamus to the pituitary (through the portal system) a >peptide.< Why peptide rather than protein?
Very short
Urea, answer one: (1) Referring to energy metabolism, why do we make this? Or (2) What are the precursors?
1 nitrogenous waste when a.a.used as calories 2 NH3 (ammonia) and carbon dioxide
"Fatty acids are chopped down two carbons at a time." Where, specifically, does this 2-carbon segment go to generate ATP.
Right to acetyl co-A in Krebs
When the insulin receptor dimerizes upon activation by insulin, answer either (1) What is the result of this enzymes activity? (2) What molecule does this enzyme act on? Or (3) Where did the phosphate come from?
1 phosphate gets added to tyrosine 2 the insulin receptor itself 3 ATP
For cellulose, answer either (1) Describe it's structure. (2) How is it dealt with in your digestive system? Or (3) How do cattle and termites digest it?

a polymer of glucose with bonds that make it indigestible for humans, hence fiber, bulk. microbes in the guts of cattle and termites help them utilize this source of glucose

"The beta-adrenergic receptor crosses the membrane 7 times." Give (and justify) one level of protein structure (related to primary to quaternary) for this G protein coupled receptor.

primary (sequence of amino acids) of course, secondary - alpha helices

Epinephrine activates a beta-adrenergic receptor on the liver cell with the end point being the release of glucose to the blood stream. Give me one of the next two molecules downstream in this signal transduction cascade.

G protein, adenylate cyclase

"Protons run through a membrane molecule like water through a water wheel to generate ATP." Answer either (1) What was the energy source to create that proton gradient? Or (2) Where is this taking place in the cell?

electron transport in the inner mitochondrial membrane


What does a cell in adipose tissue do with all the glucose it takes up under the influence of insulin dependent glucose transport?

turn it to fat

Why is glucose in the urine high in untreated diabetes? Address the question of whether diabetics have kidneys that are totally unable to transport glucose.

they transport glucose like a non-diabetic, but glucose transport reaches saturation

Blood samples are taken from a mouse before and after insulin is injected and measured with a blood glucose meter. What happens to the blood glucose level?

it goes way down

Insulin is made from a precursor (a prohormone). Say something about what the molecular structure of insulin is and/or how it relates to the prohormone.

two peptide chains are linked by disulfide bonds after a peptide is cleaved and discarded

Why would the vitreous of the eye become less transparent after long-term diabetes.

leakage from blood vessels created by angiogenesis

Metabolism of glucose transported into a beta cell in the islets of Langerhans increases ATP. How does this ATP mediate the secretion of insulin?

it closes a potassium channel that depolarizes the cell causing calcium influx for vesicle release

For cAMP, answer either (1) How, molecularly, does it activate protein kinase? Or (2) How could you persuade that cAMP to stick around a little longer?
(1) binds to (and removes) inhibitory subunits (2) block its breakdown with caffeine
Suppose there were a new substance, a potential drug or poison, that increased the cytoplasmic Ca2+ level in the beta cells in your islets of Langerhans. What do you expect would happen if you tested this substance on an animal?
More insulin vesicles released, possibly leading to coma

Insulin is made from a prohormone. State one of the things that are done to make insulin from this prohormone.

A peptide fragment is removed from between the 2 that are part of insulin and these are linked by 2 disulfide bonds

The long term health of a person with type 1 diabetes is best if the right amount of insulin is given, keeping the person's blood sugar just above the level that would result in coma. What would happen if less than that amount of insulin were injected one time?

the blood glucose would not be quite as low, that's all

Answer either (1) for gluconeogenesis, where did the glucose come from? Or (2) for ketogenesis, where did the ketone bodies come from?

1 from amino acids, 2 from triglycerides

Suppose there were a new substance, a potential drug or poison, that depolarized all the beta cells in your islets of Langerhans. What do you expect would happen if you tested this substance on an animal?

more insulin release, lower blood glucose, maybe coma

What is the ligand that closes the K+ channel in the beta cell's mechanism for monitoring glucose?


What is the activity of the insulin receptor enzyme?

tyrosine kinase

What is the polymer of glucose that is so important in muscle and liver metabolism?


In the process where epinephrine causes glucose release from liver, what enzyme does cAMP activate?

protein kinase A

In fasting, gluconeogenesis can provide some glucose from amino acids. Where do these amino acids come from?


If you had a lot of ketone bodies, what does that tell you about what is going on in your metabolism?

you are using fats, probably fasting

How is glucose detected by b cells in the islets of Langerhans?

being metabolized to make ATP, ligand for channel

Insulin injected into an anesthetized mouse would decrease blood glucose. What other hormone, normally produced in the islets of Langerhans, would raise the glucose levels back?


When I remind you that the insulin receptor is a tyrosine kinase, where is tyrosine and what happens to it?

on intracellular side of enzyme, tyrosine (amino acid) becomes phosphorylated

Epinephrine, acting on the beta adrenergic receptor, causes what to happen to glycogen in the liver?

breakdown to glucose and release to bloodstream

In addition to facilitated diffusion, there is a transport mechanism for glucose requiring energy delivery from ATP. To what molecule does ATP deliver its energy?

the sodium pump

The insulin receptor dimerizes when it binds insulin. What do these molecules do that gives them the description "tyrosine kinase?"

they phosphorylate the amino acid tyrosine

If you need to take insulin, why do you need to inject it?

if you ate it the protein would be broken down

As it applies to diabetic retinopathy, what is angiogenesis?

formation of new, fragile, blood vessels

What holds the two peptide chains of insulin together?

disulfide bonds

What process is mediated by the entry of Ca2+ into the pancreatic beta cell?

release of vesicles

What allows the return of the inhibitory subunit to the catalytic subunit of protein kinase in the signal transduction pathway for glucagon?

conversion of cAMP to 5'AMP

Under what circumstances would ketone bodies be released from the liver?


What would insulin cause an adipose cell to do?

take up glucose

What donates the phosphate when the insulin receptor gets phosphorylated?


"Insulin is a receptor tyrosine kinase." Receptor - it is a receptor molecule." Kinase - it is an enzyme that phosphorylates proteins. What does the word tyrosine imply?

it is the amino acid that gets phosphorylated

Why can't you just swallow insulin (instead of injecting it)?

would be broken down in digestion

How is cAMP made? (Answer either [1] what is the precursor? or [2] what is the enzyme?)

ATP -> adenylyl cyclase

Facilitated diffusion for glucose transport does not utilize ATP. Under what circumstances does ATP get used for glucose transport?

Indirectly, Na+K+ATPase, to let Na+ drive co transport in kidney tubule and gut

What would an injection of glucagon do to the blood glucose level?

raise it

I repeated the point "Insulin increases glucose transport into cells in insulin-dependent tissues like liver, muscle and adipose tissue." What is the most important non-insulin-dependent part of the body?


What is gluconeogenesis?

forming glucose from other molecules such as amino acids

What special job is there for the ATP that is generated by glucose metabolism in the beta cell of the islets of Langerhans?

ATP is ligand that closes K+ channel to depolarize cell

What is released from adipose tissue under the influence of glucagons?

fatty acids

Give one phrase to describe Type 2 diabetes.

non-insulin dependent, correlated with overweight, affecting receptor, occuring at a later age

What happens to the translated amino acid sequence to make the final insulin hormone?

part gets cleaved off, 2 chains linked by disulfide bridges

Why would the physician deliberately burn holes in the retina (laser photocoagulation)?

to decrease angiogenesis in diabetes

If the insulin/glucagon ratio favored gluconeogenesis, what would be happening to the insulin dependent cellular uptake of glucose?


Under what circumstances would muscle be broken down for energy?


With respect to your eating habits, when would ketogenesis occur?


What happens to the membrane voltage when glucose signals a beta cell in the islet, and how is ion flow affected to cause this electrical change?

depolarize, K+ flow decreased

How does cAMP activate PKA?

pull inhibitory subunits off catalytic subunits

What is the circuitous route by which cortisol causes the increase in blood glucose?

muscles release amino acids that are converted to glucose in the liver

What is proinsulin, and how is this processed to make the active hormone?

It is a longer polypeptide, a chunk is chopped out of the middle, and the two parts of insulin are tied together by disulfide bonds

How does destroying part of a diabetic's retina preserve vision?

It decreases the signal for angiogenesis

During fasting, what will happen to the level of ketone bodies in the blood?


What hormone promotes the storage of triglyceride into an adipose cell?


How, specifically, is Ca2+ involved in how beta cells put out insulin?

When the beta cell depolarizes (ATP closes K+ channel) Ca2+ comes in, involved in insulin vesicle release

he "water turbine" to generate ATP

"Tyrosine kinase" - where did the phosphate come from?

ATP donates the phosphate there (and pretty much everywhere)

Amino acids can be used for catabolic energy. Where do they feed into the metabolic mill?

Into pyruvic acid just before acetyl co-A

What would a beta adrenergic receptor on a liver cell mediate?

Via cAMP, increase conversion of glycogen to glucose

What pancreatic hormone is increased during fasting?


"ATP is the ligand that closes the K+ channel in the islet's beta cell." What does this do to the electrical potential?


What effect does cortisol have on adipose tissue?

Cause release of free fatty acids

For glucose transport across the membrane, answer either (1) How does insulin cause an increase [in glucose transport] for facilitated diffusion? Or (2) Why, for a different type of transporter, is energy (in the form of ATP) required?

more transporters (GLUT-4) are deployed to the membrane, for the sodium glucose cotransporter, sodium then needs to be pumped

Why would you go into shock if too much insulin were injected?

insulin sensitive tissues like muscle woulddecrease blood glucose leaving too little for brain function

What effect would glucocorticoids, glucagon and epinephrine have on adipose tissue?

release free fatty acids

For insulin, answer either (1)Why would you need to inject it (i.e., why can't you take it by mouth? (2) How does it look relative to the precursor molecule from which it is made?

proteins would be digested, larger protein was clipped to 2 fragments bound with disulfide bonds

Why does laser photocoagulation slow the progress of diabetic retinopathy?

decreases angiogenesis signal

Gluconeogenesis would result from what change in the ratio of insulin and glucagon?

I/G low, i.e. glucagon mobilizes new glucose formation formation

Beyond its function as the "currency for energy," what important function does ATP have in the beta cell of the islets of Langerhans?

intracellular ligand, ultimately for insulin release

By what molecular mechanism does cAMP activate protein kinase A (A-kinase)?

2 cAMPs each bind 2 inhibitory subunits to activate 2 catalytic subunits


Ventricles fill during most of ventricular diastole. Toward the end of ventricular diastole, there is a small increase in the filling curve that had otherwise pretty much reached asymptote. What is the cause of this small final amount of ventricular filling?

the atrial beat

For your BME senior project, you invented a device that will read out pressure in the left ventricle as a function of time noninvasively. When you present this at the senior legacy symposium, your sophomore physiology professor comes up and says "Great, but an ordinary cuff on your arm would give you additional important information missing from your readout." What important information?

the diastolic blood pressure (in the arteries)

Within the intercalated disk. there are specializations (called what?) that allow the action potential to be transmitted from one myocardial cell to the next?

gap junctions

"The T wave represents the repolarization of the ventricles." Why was there no equivalent wave representing the repolarization of the atria?

it was hidden under QRS

CPR does not restart a heart in ventricular fibrillation. Then why would it save the victim's life before emergency medical personnel arrived with a defibrillator?

keeps a little oxygenated blood going to the brain

Backslosh through leaky heart valves. Answer either (1) What is the term for this that makes reference to heart sounds? or (2) What bacterial disease might lead to this?

heart murmur, rheumatic fever

After the atrio-ventricular valves snap shut but before the semilunars open, the ventricles contract and build up pressure. What happens to the volume of blood in the ventricles during this period?

it stays the same

There are many layers in an artery. Only one of these layers of cells is present in a capillary. What is this type of cell called?

endothelial cell

There is a family of curves for different amounts of sympathetic nerve stimulation where stroke volume in ml is plotted as a function of ventricular end-diastolic volume in ml. Answer either (1) What is this called? (2) In what way does this distinguish the properties of cardiac vs striated muscle as a function of length? or (3) What effect does sympathetic stimulation have on these curves?

Frank-Starling law, cardiac muscle does not get weakker as a function of length, it moves them up and to the left

Parasympathetic and sympathetic portions of the autonomic nervous system affect heart rate, acting on the SA (and AV) nodes. What additional direct affect does the sympathetic nervous system have on the heart?

sympathetic NS increases myocardial contractility

What would have to happen to the shape of the action potential of a ventricular myocardial cell to compensate for the increased heart rate that accompanies heavy exercise?

the long duration action potential would get shorter

If, for some reason, the signal that should have originated in the SA node were not transmitted appropriately, the heart would still beat. What would drive this heart beat?

the automaticity of the AV node

HCN channels. Answer either (1) What is the cyclic nucleotide referred to by "CN?" or (2) What do we call the unusual electrophysiology mediated by the HCN channel?

cAMP, pacemaker potential or diastolic depolarization

"Here, quick, chew this aspirin and drink it down." If this stopped a heart attack in progress, how would it do that?

inhibit clotting

"Action potentials that originate in the SA node pass from one atrial myocardial cell to another and usually usually trigger the AV node before it would have fired automatically." Say why spreading from one myocardial cell to the next is not a full explanation of action potential spread in the ventricles.

bundle of His, bundle branches, and Purkinje fibers get the action potential to the apex first

Name one of the 4 risk factors for heart attack that ranks higher than family history.

high blood pressure, prior heart attack, smoking, diabetes

For the atrial beat, answer either (1) Why does it contribute only minimally to ventricular filling? Or (2) What would keep the blood from flowing backward into the veins coming into the atria?

1 blood goes from atria to ventricles even before the beat, 2 nothing except those valves that are in veins

The first few moments of ventricular contraction fail to move blood into the arteries. Why?

isovolumetric contraction is because semilunars remain closed until ventricular pressure is higher than afterial pressure

You feel chest pain so you take nitroglycerine. How did this save you from a heart attack?

relaxation of smooth muscle in coronary arteries would alleviate the block (that likely resulted from a thrombus or an embolism in an artery already partially occluded from atherosclerosis)

Why do the textbook artists color the pulmonary arteries blue?

they carry blood low in oxygen and high in carbon dioxide

Why can you hear the brachial artery below the blood pressure cuff when the cuff pressure is between the systolic and diastolic levels?

Korotkoff sounds are when blood flow is turbulent from partly closed artery

In the atria, all that was needed to propagate the electrical signal was the connections from one myocardial cell to the next. For the ventricles, why was it important to have the added feature for propagation (bundle of His and bundle branches)?

to start the contraction at the "apex" (bottom), to send the action potential quickly

Three "leads" describe 3 different ways both wrists might be fed in for measuring the ECG. Why might different people have differences in how the ECG looks with the 3 leads?

orientation of heart (axis) can differ, abnormalities like murmurs might create an asymetry in heart muscle

What would the sympathetic nervous system do to the shape of a myocardial cell's action potential?

shorten that prolonged spike

A person drops over and has no pulse. To keep him or her alive until medical equipment and personnel arrive, (answer either) (1) What is the name of the procedure you would perform? Or (2) How would this keep the victim alive?

CPR, it keeps the brain alive

"Re-entry of excitation:" After recovering from a heart attack, why might some myocardial cells be excitable (no longer refractory), and be triggered to fire, before the appropriate time (that appropriate time being the time synchronized from the SA and AV nodes)?

a pathway of myocardial cells around the scar might be long

Why was a reminder of the process of receptor-mediated endocytosis by clathrin-coated pits relevant in the context of heart attacks?

LDL is removed by that process

Approximately what is the pressure in the left ventricle when the semilunar valve (to the aorta) opens?
At that moment it should equal diastolic pressure
Opening up the arteriovenous anastomoses would do what to blood flow in the capillary loops in the dermis?
It would bypass (therefore decrease) blood flow in the capillary loops of the dermis
The parasympathetic output to the heart affects both the SA and the AV nodes. What affect in addition to these two does the sympathetic output to he heart have?
It affects contractility in the myocardium in addition to affecting rate via the nodes
How would the sympathetic nervous system affect the shape of a series of action potentials recorded from a cell in the SA node?
Diastolic depolarization (pacemaker potential) would reach threshold faster (and the rate would go up)
Why is the expression "referred pain" sometimes applied to the pain experienced during a heart attack?
Pain from viscera and heart is projected onto the somatosensory map, thus for the heart, classic symptoms of shooting pain in left shoulder and neck especially in men
When, in the heart cycle, do the bicuspid and tricusid valves snap shut?

at the beginning of ventricular contraction

What kind of blood vessels have the highest TOTAL cross sectional area?


What does the last Korotkoff sound signify?

the diastolic (arterial) blood pressure

What are the cells that line blood vessels including capillaries called?

endothelial cells

Why is the wall of the ventricle thicker than the wall of the right ventricle?

systemic circulation is higher pressure than pulmonary

What is Einthoven's triangle?

Hook-ups for diagnostic EKG Leads I, II, and III on 2 wrists and left ankle

Long QT Syndrome, diagnosed by a lot of time between the QRS and the T, affects a channel (for what ion?) involved in the repolarization of ventricular myocardial cells?


Cells in what areas depolarize automatically during diastole?

SA node

Although the electrical signal would pass from one myocardial cell to the next, specialized fibers hurry it to much of the ventricular muscle synchronously. What are these fibers?

bundle of His, bundle branches, Purkinje fibers

Why would you die of if there were too much time between heart failure and defibrillation without CPR (cardio-pulmonary resussitation)?

brain would die without O2 (and glucose)

The time between the QRS and the T represents the duration for what specific cell type?

ventricular myocardial cell

For a normal person, slow Ca2+ channels would control heart rate in which specific part of the heart?

SA node

In good health, what part of the body clears LDL (and HDL) from the blood stream?


How does nitroglycerine help to relieve angina pectoris?

relax artery smooth muscle

What is the likely mechanism that antioxidants might prevent heart attacks?

oxidized LDL is bad

Why isn't an atrial beat needed for most of the venous return to go to the ventricles during diatole?

tricuspid and bicuspid valves are open

What does the endothelium line?

blood vessels

If you took statins, what substance would decreased?


How do gap junctions contribute to heart function?

get action potential from one cell to another

Since there is not much blood pressure left, what is needed to help blood flow along in veins?


Taking blood pressure, you inflate the cuff to 180 mm Hg, then lower it. You hear nothing until the systolic pressure is reached. After the diastolic pressure is passed, you hear
nothing. Why do you get sounds only between systolic and diastolic pressures?


What causes the second heart sound at the end of systole?

semilunars snap shut

How does aspirin help to prevent heart attacks?

inhibits platelet aggregation

Where does the vena cava (superior and inferior) empty into?

right atrium

At the moment the semilunar valves open, what is the blood pressure in the left ventricle?

same as arterial diastolic

What is the function of an arteriovenous anastomosis?

shunt blood from peripheral vascular bed

What is the endothelium?

cell lining of blood vessels

What is a heart murmur?

a leaky valve

Compare the duration of the isovolumetric portion of the ventricular contraction for someone with high diastolic blood pressure with that for a normal person.

the ventricle would contract further before forcing open the valves to arteries (for high b.p.)

What regulates the precapillary sphincter?

the sympathetic nervous system

"CN" in "HCN channels" stands for "cyclic nucleotide." What do cyclic nucleotides have to do with pacemaker cells?

adrenergic receptor affects cAMP level

Explain the interval between the QRT complex and the T wave in terms of the shape of the myocardial action potential.

that is a long action potential, QRS is depolarization, T is repolarization

How could you get a heart beat if there were no trigger from the SA node?

Eventually the AV node would kick in

At the moment of the last Korotkoff sound, what does the pressure dial show?

diastolic b.p.

What are baroreceptors in the carotid sinus used for?

regulate b.p.

In addition to increasing contractility, what does sympathetic input to the heart do?

regulate heart rate

What is ischemia?

interuption of blood flow and hence oxygen supply

What does a defibrillator do to save your life?

starts heart again, makes it so SA node triggers heart

What does a high HDL/LDL ratio in your blood test results imply?

less risk for coronary artery problems

As opposed to apoptosis, what is the damage to cardiomyocytes in a heart attack?


What is it called when you have pain in parts of your body, like your left arm, in a heart attack?

referred pain

What is a thrombus and why is it potentially damaging?

a blood clot that clogs the artery

What event occurs at the end of the isovolumetric contraction of the left ventricle?

Aortic semilunar valve opens

Why do veins need to have valves to ensure forward blood flow while arteries do not?

there is no blood pressure driving the blood

In what way does the Frank-Starling law differ from the striated muscle's length-tension curve?

FS-More stretch (ventricular filling) more contraction, striated weaker when muscle is long

Why is the first part of the ventricular contraction isovolumic?

Bicuspid and tricuspid are closed, semilunars do not open until ventricular pressure > arterial

Heart cells die by cell damage, rather than by programmed cell death (apoptosis). What is the term used for this kind of damage?


A blood test shows that a patient has a high HDL to LDL ratio. What does this mean?

these are good numbers re artery health

In an arteriole, what would a precapillary sphincter do under the influence of the autonomic nervous system?

open or close to regulate blood flow to the capillary bed

What valves close right at the start of ventricular contraction?

tricuspid and bicuspid (atrioventricular)

Hyperpolarization cyclic nucleotide (HCN) channels are important in pacemaker cells. Name the relevant and famous cyclic nucleotide, the one controlled by beta-1 adrenergic receptors.


In atria, the action potentials are passed from one myocardial cell to the next. Why are there additional fibers (bundle of His, bundle branches, and Purkinje fibers) for ventricles?

to speed the action potentials to the base

Parasympathetic fibers slow the SA and AV nodes below their rate of automaticity. What nerve is this?

vagus, 10th cranial

Above the systolic pressure and below the diastolic pressure, you hear nothing. Why are there Korotkoff sounds between systolic and diastolic pressure?

blood flow is turbulent

What does the Wiggers diagram tell us about the opening of the aortic semilunar valve when the diastolic blood pressure is high?

ventricular pressure would have to be higher to push open the valve

Give an approximate value for the blood pressure in the ventricles during diastole.


What symptom would be noticed if the heart muscle were to attempt anaerobic metabolism?

pain (angina)

What do aspirin, coumaden and the rat poison WARFarin have in common?

they inhibit coagulation

Valves between where and where snap shut at the beginning of ventricular contraction?

atria and ventricles

For part of the heart cycle, ventricular and arterial pressures are equal. How do these two pressures relate the rest of the time?

in diastole, ventricular is lower than arterial

What holds shut the aortic and pulmonary semilunar valves during the beginning of ventricular contraction?

arterial pressure

In addition to the automatic tissues (predominantly SA & AV nodes) to what does the sympathetic nervous system connect and why?

heart muscle to increase contractility

Electrically, what do pacemaker cells during diastole?


How come the electrocardiogram can reach as far as the wrists and ankles for recording?

virtually no extracellular resistance

What would happen to the time between Q and T waves with sympathetic activation?


What is the difference between a thrombus and an embolism?

thrombus clot forms locally, embolism dislodged from elsewhere and arrives at trouble spot

Why would a large area of damage in the heart lead to re-entry of excitation?

the distance from cell to cell to cell would have the spike arriving after the refractory period is over

What type of cell is used for continuous and fenestrated capillaries?


What is it that may shunt blood from arteriole to venule to bypass capillary bed in the skin?

arteriovenous anastomoses

In what way is heart muscle different from striated muscle with respect to strength as a function of length?

Frank Starling law has it that fuller (more stretched) ventricle has higher contractility, while striated muscle tension drops off

As cuff pressure is being released, between the systolic blood pressure and the diastolic pressure, your figure indicated that you get "sounds at every systole." Why?

turbulent blood flow

How would nitroglycerine help if you felt a heart attack coming on?

relax smooth muscle in artery

Describe referred pain as it refers to heart attack.

projected to neck, arms

What is it that makes the bicuspid and tricuspid valves close to make the first heart sound ("lub")?

pressure in the ventricles closes these atrio-ventricular valves

Why might a person pass out if (s)he stands without moving for a long time?

muscular contraction contributes to venous return, hence venous pooling

What part of the nervous system would regulate the precapillary sphincter?


During ventricular systole, just when the pressure forces the aortic semilunar valve open, what is the arterial blood pressure?

equal to the diastolic pressure right then

About what fraction of ventricular filling is from the beat of the atria?

a very small amount, the figure shows about 10 out of 80 ml

What happens to the brachial artery when the blood pressure cuff is first fully inflated?

it is completely closed

Suppose your SA node failed to fire. You would probably still have a heartbeat (how?) and it might be reasonably adequate (why?).

AV node would fire, see q 10, most of the ventricular filling does not rely on atria

What happens to the electrical potential of a cell in the sinoatrial (SA) node during diastole?

there is diastolic depolarization in these pacemaker cells until threshold is reached

How do we get recordings from 3 different "leads" in Eindhoven's triangle starting with a positive electrode connected to one wrist, a negative electrode connected to the other, and ground connected to an ankle?

The three so-called "leads" are gotten by swapping (2 at a time) connections to the 3 locations

Before paramedics arrive with the defibrillator, why is cardiopulmonary resuscitation essential?

CPR delivers enough oxygenated blood to the brain to keep it alive

"The bad news is that your cholesterol is high. The good news is that your ratio is good." What would be a good ratio (when the cholesterol level is broken down into its components)?

If HDL/LDL is high

At the peak of systole, how does the pressure in the right ventricle compare with the pressure in the left ventricle?

Way lower pressure in pulmonary circulation

Both branches of the autonomic nervous system (sympathetic and parasympathetic) connect to both nodes of the heart(SA and AV). In addition, the sympathetic nervous system also makes additional connections to the heart (to where? Or for what purpose?).

to muscle to increase strength of contraction

What would happen to the Q-T interval during strenuous exercise?


What is the function of an arteriovenous anastomosis?

Shunt blood to bypass capillaries in skin to prevent heat loss

What is the status of bicuspid and tricuspid valves during diastole?

open and blood gushes from atria to ventricles

"Fenestrated endothelium." Explain either (1) fenestrated or (2) endothelium.

windows (holes) in layer that lines blood vessels (capillaries

How would nitroglycerine give you relief?

relax smooth muscle, coronary arteries more patent to relieve angina

Why does blood flow more slowly in capillaries than in arteries?

there is a greater cross sectional area

Why do the atria contribute only minimally to the ventricular filling during diastole?

because blood flows to ventricles during diastole b/c A-V valves are open

Even before ventricular pressure overcomes arterial diastolic pressure, increasing ventricular pressure does (what?) to (what valves?).

snaps shut A-V valves

What did pumping the blood pressure cuff up to 140 mmHg do? (Assume you have a subject with fairly normal blood pressure.)

close brachial artery

"The heart is an electrical syncitium" because of what specialization?

gap junctions

What is the channel critical for diastolic depolarization (pacemaker potentials)?

HCN hyperpolarization cyclic nucleotide

Why would you prescribe an inhibitor of angiotensin converting enzyme to a patient?

decrease blood pressure

What is the difference between plaque and a thrombus in arterial occlusion?

plaque builds up in artery wall b/c of cholesterol, thrombus is blood clot

What would have to be wrong with a patient to warrant shocking the chest with paddles and why would that help?

ventricular fibrillation, i.e., heart electrical activity flat lines

What is the status of the semilunar valves during diastole?


How does the nervous system regulate precapillary sphincters?

sympathetic nervous system causes vasoconstriction or hyperemia

What do the carotid sinus and aortic arch have to do with the regulation of the heart?

Pressure receptors feed to brain to regulate heart output

Myocardial cells are electrically connected via gap junctions. Why, then, was it useful to have bundle of His, bundle branches, and Purkinje fibers?

gets action potential to heart apex so that ventricular contraction ejects blood optimally

What do aspirin, rat poison and the heart have to do with each other?

aspirin and WARFarin would inhibit clots (thrombus or embolism) in coronary arteries

Referring to the Wiggers diagram, why would high diastolic blood pressure be especially hard on the heart?

higher ventricular pressure would be required to force open semilunar valves


What would stimulation of beta-2 adrenergic receptors do to the air flow in trachea and bronchi?

open airways, increase air flow

Answer either (1) why oxygen in the air we breathe has a partial pressure lower than 760 mm Hg, or (2) why the oxygen in alveoli has a lower partial pressure than the oxygen than the air that we breathe.

only about 20 % of the air we breath is oxygen, then, the value is further lowered by the high carbon dioxide and water in the lungs

The total lung capacity equals the tidal volume plus (what)? Hint, there should be several components to your answer.

inspiratory and expiratory reserves plus residual volume

A healthy individual has an injury resulting in pneumothorax. In what direction? and how much (approximately)? does the pressure in the pleural cavity change? (answer both)

it goes up a tiny bit about 5 mmHg

What specialization in the trachea powers the mucus elevator?


Epinephrine would help a person having an asthma attack. What completely different approach could be used, in this case to control inflammation?

antileukotriene like Singulaire

Name one component that separates air in the alveloi from red blood cells.

type I alveolar cell, basal lamina, endothelial cell

The partial pressure of carbon dioxide in the pulmonary vein is 40 mm Hg. What is the partial pressure of carbon dioxide in the systemic arteries?

duh! there was no gas exchange between the two

"Water's surface tension would tend to collapse (close) alveoli." Answer either (1) How does physiology take care of this problem? or (2) People with what condition have a real problem because of this?

surfactant, premature babies

"The buffering capacity of blood keeps high carbon dioxide from changing pH much." Then how does physiology improve on this sensitivity in chemoreceptors in the medulla?

on that side of the blood brain barrier, the cerebrospinal fluid has no buffers

The partial pressure of carbon dioxide in the pulmonary vein is 40 mm Hg. How would hyperventillation affect this?

cut it in half

Why do people with emphysema need to breathe more?
With fewer alveoli, there is less area for gas exchaqnge
In what way is the coating of water in the alveoli different with vs. without surfactant?
With-it has lower surface tension than without
For cystic fibrosis, (answer one of these) (1) A gene, mutated in cystic fibrosis, codes for what? (2) What are the symptoms? Or (3) How does the parent treat those symptoms on a daily basis?
CFTR, a chloride channel
What happens to ventilation when pH goes down in the cerebrospinal fluid (CSF) of the medulla oblongata at the confluence of integrating inputs from aortic and carotid bodies, the pneumotaxic center and the apneustic center?
More acidity implies more carbon dioxide, so you breathe harder
Pick one: (1) A drug that specifically affects beta-2 adrenergic receptors (terbutaline), or (2) a drug that blocks leukotriene action (Singulair). What is the specific action that would help in asthma?

1 open airways by mimicing adrenalin or the sympathetic nervous system, 2 decrease inflammation

The partial pressure for oxygen in the atmosphere is atmospheric pressure times the fraction of the atmosphere that is oxygen. What are the major reasons that the partial pressure for oxygen in the alveoli is much lower?

there are higher proportions of water vapor and carbon dioxide

You have a subject and a spirometer. What value, a portion of total lung capacity, cannot be obtained?

residual volume

Give either the approximate number or the value relative to atmospheric pressure of the intraplural during inhalation.

book says 754 mm Hg, the point is that it is slightly less than lungs which are slightly less than atmospheric

Why does a premature baby have trouble breathing?

type 2 alveolar cells mature late and without surfactant, water pressure impedes alveolar opening

Where, other than the medulla oblongata, are chemoreceptors located that feed by nerves to the respiratory control centers?

aortic and carotid bodies

Relative to curve where % oxygen saturation is plotted as a function of partial pressure for oxygen for adult hemoglobin, how would you place the curve for fetal hemoglobin?

fetal oxyhemoglobin dissociation curve is to the left of the adult

Why does chloride come out of red blood cells in the lungs?

so bicarbonate can come in for the generation of carbon dioxide to be exhaled

If you hyperventillated, what would become of the pH of the cerebrospinal fluid?

less CO2, pH goes up

What is the biological word for the Adam's apple?


Expiratory reserve plus inspiratory reserve plus tidal volume equals what?

vital capacity

What is the chloride shift?

Cl- goes into erythrocyte when HCO3- comes out and vice versa

What is the intrapleural pressure? (I want an approximate value.)

slightly less than atmospheric

What two gasses have much higher partial pressure in alveolar air than in inspired air?

H2O, CO2

What are the pneumotaxic center and the apneustic center used to control?

respiratory rhythm

Cystic fibrosis is a channel for what ion?


An asthma spray would contain an agonist for what naturally ocurring neurotransmitter?


Where are the brain centers that control breathing?

medulla and pons area

The abscissa (X-axis) of the oxyhemoglobin dissociation curve is partial pressure of O2 in mm Hg. What is plotted on the ordinate (Y-axis)?

% saturation (with O2) of hemoglobin

What compound (related to but not the same as prostaglandins) constricts bronchial smooth muscle (blocked by Singulair)?


One reason that the partial pressure of CO2 is higher in alveoli than in the atmosphere is that cells generate CO2 (as waste). What is the other reason?

not all the air in the lungs is exchanged by breathing

Partial pressures for CO2 and O2 are almost equal in alveolar air and pulmonary veins. For which gas is there a greater difference between alveolar air and pulmonary arteries?


Which component of lung volume cannot be measured with a spirometer?

residual volume

What is the naturally ocurring hormone for beta-2 receptors in bronchi?


What is the highest level that mercury would rise in a glass tube with a vacuum at the top?

760 mm

Respiratory distress syndrome in premature infants results from the lack of what molecule?

surfactant (phosphatidyl choline)

Where do chemoreceptors in aortic and carotid bodies feed to to control breathing?


What would alkaline cerebrospinal fluid do to breathing?

inhibit it

In pneumothorax, what compartment increases its pressure to that of the atmosphere?


In addition to containing heme, how would you describe the molecular structure of hemoglobin?

2 alpha and 2 beta protein chains

A figure in your text indicated that one place was responsible for "automatic breathing," while I cautioned you that this was very different from automaticity in the heart. What is this place that generates automatic breathing?


Bicarbonate in plasma helps in CO2 transport. It is made with the help of what enzyme in what cell?

carbonic anhydrase in red blood cell

What would O2 on mother's hemoglobin do when it gets near fetus hemoglobin in the placenta?

offload to fetal

When is the pressure in the alveoli slightly higher than atmospheric?


The total lung capacity is tidal volume + inspiratory reserve + expiratory reserve + what?

residual volume

What is the significance of the value 760 mm Hg?

atmospheric pressure at sea level

Why does a mutant chloride (Cl-) channel (CFTR specifically) lead to lung disease?

poor ion transport -> poor water transpord -> viscous mucous

For the sake of CO2 transport, where is bicarbonate (HCO3-) made and where is it carried?

made in RBC, carried in plasma

Why is the partial pressure for alveolar H2O much higher than for H2O in inspired air?

air is humidified, usually in nasal passageways

What common effect (though to different extents) do leukotrienes and the parasympathetic nervous system have on bronchioles?

decrease air flow

What does emphysema do to the number of alveoli?

decrease since adjacent ones merge

Why is the partial pressure for CO2 higher in the pulmonary artery than in the alveoli?

pulmonary artery carries CO2 offloaded by tissue respiration

Although phosphatidylcholine is best known as a membrane phospholipids, it also has a special function in the lungs. What is this function.

component of surfactant, decrease surface tension of water

You breathe in and out your vital capacity a dozen times in rapid succession. What is this called and why would your urge to breathe be decreased for the next minute?

hyperventillation, by blowing off CO2, less H+ in medulla

A stab wound to the chest can lead to the collapse of a lung because what compartment would increase its pressure to atmospheric pressure?

intrapleural space

What is the important nerve connecting the heart and the brain that carries chemoreceptive signals from the aortic bodies?

vagus (10th cranial)

Why would you want to inhale adrenalin? (Your answer can address pathology, cells or molecules.)

asthma, relax smooth muscle, open bronchial airways, activate beta 2 adrenergic receptors

Why is the partial pressure of oxygen lower in alveoli lower than in the outside air?

because water vapor and carbon dioxide fractions are so much higher

A slight increase in pressure (where?) would allow the lung to collapse if there were a stab wound to the chest?

intrapleural space

Why would asbestos be more likely to stay in the lungs of smokers than of non-smokers?

smoking paralyses cilia

How does intrapleural pressure relate to alveolar pressure (at rest, breathing in and breathing out)?

a little lower in all cases

Why would it take more effort than a premature baby could muster to breathe?

there is no surfactant to decrease water tension

Name one of the two nerves that carry chemosensory input to the brain to control respiration?

glossopharyngial (9th) and vagus (10th)

Why is it so useful to monitor pH of the cerebrospinal fluid to report the need to breathe?

carbon dioxide would make pH go down

What does the sympathetic nervous system do in bronchi? (Your answer can either be at the level of the cellular response or of the passageway function.)

beta 2 receptors relax smooth muscle open airway

What could you do to lower the partial pressure of carbon dioxide in your alveoli?


Give a ballpark figure for the partial pressure of carbon dioxide in the arteries for normal breathing and for hyperventilation.

40 mm Hg, less if hyperventillate

Why does chloride need to go in and out of red blood cells?

to move bicarbonate to plasma where there is room to carry it

Why wouldn't you expect inhibitors of prostaglandin synthesis to help with inflammation in asthma?

Leukotrienes, not prostaglandins

Total lung capacity minus expiratory reserve minus inspiratory reserve minus residual volume equals what?

Tidal volume

What happens to the pressure in what compartment to cause the lung to collapse?

Intrapleural becomes equal to atmospheric

Other than the medulla (of the brain), where are there chemoreceptors to control ventilation? (or, if you prefer, tell me how they feed to the brain.)

aortic and carotid bodies

What is the purpose of cilia in the trachea?

to sweep gunk captured in mucus up to where it gets swallowed

How would epinephrine in an inhaler affect breathing? (Your answer could apply to molecular type of the receptor or to affect on the airway.)

beta 2, dilate (open) bronchioles

What is it that would make mercury go up 760 mm in a glass tube?

atmospheric pressure (not "suction")

Give at least 2 reasons oxygen's partial pressure is so much lower in alveoli than in the atmosphere.

our of 3: (1) there is so much CO2 in alveoli, (2) there is so much H2O in alveopi, (3) not all air is exchanged each breath

The partial pressure for carbon dioxide in the pulmonary artery is 46. What is it in the pulmonary vein?

lower, but not that much lower (40)

Why would they put premature babies in high oxygen?

lack of surfactant makes breathing difficult

Relative to carbon dioxide, how much oxygen is carried in the plasma?

O2 is way less soluable in water than CO2 (the figure clearly showed 10% for CO2, another figure implied about 1.5 % for O2)

"Most bicarbonate is carried in the plasma." But it was made in the erythrocyte. What trickery was used to move it to the plasma?

exchange with Cl-

"Mucus elevator." Relate to the conventional wisdom about the interaction of asbestos and smoking.

smoking paralyses cilia so asbestos gets stuck in lungs worse

What would the sympathetic nervous system do to the air passageway opening?


The partial pressure of O2 in the atmosphere is 159 mm Hg. Give a reason it is much lower in the alveoli.

lowered b/c water and CO2 are high

You are studying the respirometer record of a patient. What is the one volume you cannot ascertain from this record?


Why might a lung collapse from a piercing stab wound to the chest?

intrapleural pressure becomes atmospheric pressure

Why does surfactant make breathing easier?

decreases surface tensiol

What information is carried from the aortic and carotid bodies to the brain to control breathing?


How does the ionization of carbonic acid into H+ and HCO3- in the red blood cell greatly increase the amount of carbon dioxide that can be transported?

then bicarbonate can be sent to the large volume of the plasma

Why would you expect that aspirin and ibuprofen would not help you with inflammation in the trachea and bronchi?

caused by leukotrienes not prostaglandins

Why would breathing be difficult in a premature infant?

surfactant secreting cells are not mature yet

What must happen to compensate for bicarbonate moving from the red blood cell to the plasma?

chloride must move in

Hyperventilation typically halves the partial pressure of carbon dioxide in the lungs to a value of about (what?).

20 mm Hg


Uric acid: Answer either (1) Why would you take NSAIDS (non-steroidal anti-inflammatory drugs) if your uric acid were high? or (2) Why would you dig up uric acid from the islands off the coast of Peru?

reduce inflammation in a gout attack, for nitrogen fertilizer

In the glomerulus, fluid passes through the fenestrated capillary endothelium plus (what?) on its way to Bowman's capsule.

pedicels of podocytes

Aldosterone. Answer one of the following: (1) Where specifically is it from? (2) Where (specifically) does it act? (3) What would happen to an animal who has no aldosterone?

zona glomerulosa in adrenal cortex, ascending loop of Henle, would lose salt in the urine and crave salt

Angiotensin is activated in a low blood crisis; another hormone regulates angiotensin activation. Answer either (1) Where is this other hormone secreted from? or (2) What is this other hormone called?

JGA in kidney, renin

Why would it be advantageous for some animals to use uric acid instead of urea to eliminate nitrogenous wastes?

less water is lost

Where does the efferent arteriole from the glomerulus go to next?

vasa recta, capillary bed around loop of Henle

Where (answer either cellular location or molecule) is energy used to resorb glucose across a cell in the kidney tubule?

basolateral surface, sodium pump

ADH (antiduretic hormone, alias vasopressin). Answer (1) What channels are regulated by ADH? or (2) Where (specifically) does ADH have its effects?

water channels (aquaporins), collecting duct

Why is it advantageous for some animals to use uric acid rather than urea in their excretory systems?

less water is lost

26. "Upwelling of nutrients off the coast of Peru." Answer either (1) What ocean current helps with this? Or (2) What is the climate abnormality that disrupts current and upwelling?

Humboldt current, El Nino

27. Non-steroidal anti-inflammatory drugs (NSAIDS) inhibit the formation of what mediator of inflammation?


Peritubular capillaries (the vasa recta) form part of the kidney's portal system. Where is the other capillary bed?

the glomerulus

A basement lamina separates two components of the glomerular sieve. Name one of these two cellular components.

podocyte's foot processes and fenestrated capillary

Facilitated diffusion for glucose takes place on the basolateral surface of a proximal tubule cell. For EITHER of the other two essential components of glucose transport in this cell type, give BOTH the membrane transporter PLUS the location of the membrane.

cotransport-apical, sodium pump-basolateral

What function does it serve to have salt but not water transport in the ascending limb from the loop of Henle?

to increase the osmolarity of the interstitial fluid

Elimination of what hormone from your body would make you crave salt?


ACE=angiotensin converting enzyme: Answer EITHER (1) What hormone from the kidney activates ACE? Or (2) For what disorder might you want to inhibit ACE?

renin, hypertension

People with gout have high levels of what substance?
Uric acid
Many people enjoy an electrolyte replacement beverage such as Gatorade if they perspire a lot. They do not like such drinks if they pee a lot. Why the difference?
More salt is lost in sweat than in urine
For ADH (antidiuretic hormone = vasopressin), answer one of these (1) What does it do to the membrane to facilitate transport? Or (2) Where, in the kidney, does it have its effect?
Adds aquaporins (water channels) in the collecting duct
Blood arrives at the glomerulus for filtration. What do they call the blood vessel that carries blood away from the glomerulus?

efferent arteriole

In addition to facilitated diffusion at the basolateral cell surface, what is necessary for glucose transport in kidney tubule and intestinal cell? (Include process and location.)

apical cotransport with Na+

What is the product of the juxtaglomerular apparatus?


High levels of what nitrogen-containing chemical cause gout?

uric acid

Why are alcoholic beverages contraindicated to stay hydrated in times of heat stress? (Make sure your answer says what happens to the relevant hormone level.)

alcohol inhibits ADH, more water is lost through kidney

Cystic fibrosis is a channel for what ion?


Where are the cell bodies of the cells whose axon terminals release ADH and oxytocin?


What does creatinine clearance test for?

glomerular filtration

In the intestine and the kidney tubule, three processes are needed for glucose transport, (1) basolateral sodium pump, (2) basolateral facilitated diffusion, and (3) apical... [your

glucose/sodium cotransporter

Because of the portal system, the vessel carrying blood from the glomerulus is not called a vein. What is it called instead?

efferent arteriole

If a kidney stone passed from the kidney to the bladder, what tube would it go through?


What accumulates in Lesch-Nyhan syndrome?

uric acid

By what mechanism are proteins excluded from the primary filtrate in the kidney?

size of sieve openings (podocytes and fenestrated endothelium

Why might you give a secretion blocker in conjunction with penicilin?

keep antibiotic from being pumped out by kidney

Why do cells in the proximal convoluted tubule need to pump sodium to reclaim glucose?

because of sodium-glucose cotransporter ion apical surface

In what tube does the final, ADH-dependent, water reclamation occur?

collecting duct

Instead of injecting inulin, what test is there for clearance assaying for a substance already in the body?


Renin activates what hormone?

angiotensin II

In the kidney tubules, salt and water are reclaimed. Only one substance is actively transported. What substance? (Be specific.)


What hormone from the adrenal cortex is essential for salvaging salt in the kidney?


There is a capillary bed in the glomerulus. Where is the other capillary bed of this portal system?


Na+, Cl- and H2O are all recovered in the proximal convoluted tubule. Which involve active transport?


Aquaporins in the collecting ducts are regulated hormonally. What are aquaporins?

ater channels

At what location in the lumen of the kidney tubules is the tonicity the highest?

loop of Henle (and maybe deep collecting duct)

Describe either how the kidney deals with inulin or, alternatively, what specific aspect of kidney function inulin is used to test.

filters but does not retrieve, tests GFR=glomerular filtration rate

Considering how unreactive nitrogen gas (N2) is, how did it get into biological molecules such as amino acids?

nitrogen fixation

The glomeruli vs. the loops of Henle are in which two overall anatomical portions of the kidney respectively?

cortex, medulla

In addition to the fenestrations in capillaries, what cellular architecture is responsible for glomerular filtration?

pedicels of podocytes

What change in appetite would occur if the adrenal glands were removed?

you would crave salt

What is detected by the juxtaglomerular apparatus that makes these granular cells release their renin?

pressure in afferent arteriole

If you drink very little and become thirsty, what pituitary hormone would be increased?

ADH=antidiuretic hormone

What are creatinine and inulin reapectively and what are they used for?

creatinine is already in body and inulin is injected, buth used to test glomerular filtration since they are filtered but not resorbed

For glucose in the kidney, tell me the surface locations of the three transporters involved.

cotransport apical, basolateral facilitated diffusion plus sodium pump

What should happen to the tonicity of urine if a drug that inhibits ADH (antidiuretic hormone) were administered?

becomes dilute

Why are drugs like aspirin called prostaglandin inhibitors?

they block synthesis by blocking the cyclooxygenase (COX)

What is the tube that connects the kidney with the bladder?


What do they call the blood vessel exiting the capillary bed that is in the glomerulus?

efferent arteriole

Salt and water are recovered in the proximal convoluted tubule. What is active and what is passive? Be specific.

sodium ion active, chloride and water passive

Why would a rat drink salty water after an adrenalectomy?

aldosterone which favors salt recovery would be missing

Where, in the nephron's components, are the aquaporins that are influenced by ADH (antidiuretic hormone)?

collecting ducts

What does the juxtaglomerular apparatus monitor and why is it in a good location to do this job?

blood pressure, near afferent arteriole

From the renal pelvis, the urine flows to the bladder via what tube?


Why is it advantageous to have hypertonic interstitial fluid in the kidney medulla?

Then, if ADH is present, water will be salvaged from the collecting duct

Why would it be advantageous to position renin secreting cells where they are?

Blood pressure is monitored near the glomerulus for the emergency work of angiotensin that rennin initiates

Drugs that inhibit prostaglandin synthesis might help with the symptoms of gout. Why?

b/c it is the inflammatory response to the uric acid in the joint that is pain

What is wrong in Lesch-Nyhan syndrome children (HGPRTase deficiency)? (Your answer can be behavioral or chemical.)

self-mutilation, uric acid accumulation

What blood vessel connects the two capillary beds of the nephron and hence serves as the portal vessel?

the "arteriole" that is efferent from the glomerulus

Out of all the things a nephron does, inulin clearance tests for just one. What?

glomerular filtration

How is glucose transported at the apical surface of the cell of the kidney tubule?

apical is the co-transport with Na+

What would an adrenalectomy do a rat's specific appetites?

without aldosterone, there would be increased sodium appetite

What would inhibiting ADH do to the urine?

inhibiting antidiuresis, two negatives make a positive, so diuresis, more (and more dilute) urine

How and where does ATP get used for glucose resorption in the kidney?

sodium pump on basolateral surface in proximal tubule

How do water and salt transport differ in the proximal convoluted tubule vs. the ascending limb from the loop of Henle.

in both cases, sodium transport is active. Water follows in the PCT but not in the ascending limb

By what molecular mechanism would ADH (antidiuretic hormone) make the collecting duct recover water better?

add aquaporins

In describing the work of the kidneys, some relevant volumes were graphically described in terms of drums containing 55 gallons. Why were there 32 and 8 drums in that story?

32 volume of blood pumped daily, 8 through kidneys

"A disruption in the Humboldt current might have an effect on bird droppings." Fill in a few of the details missing in that telegraphic statement.

bird droppings - uric acid, nitrogen fertilizer, birds eat anchovies which thrive b/c of Humboldt driving upwelling

In the portal system of blood flow in the kidney, describe the anatomical localization of the second capillary bed (vasa recta).

surrounds each loop of Henle in medulla

In addition to foot processes (pedicels) of podocytes, how else is a fine-mesh mechanical sieve achieved in the glomerulus?

fenestrated endothelium

Why would an adrenalectomy cause an animal to have a specific appetite for salt?

loss of aldosterone makes kidneys lose salt

What change of appetitive behavior would accompany an increased secretion of ADH (antidiuretic hormone)?

while kidneys wold conserve water, you would also be thirsty

For hormonal control originating from the juxtaglomerular apparatus, answer either (1) What purpose does it serve? Or (2) Why is the location of the juxtaglomerular apparatus ideal for monitoring this need?

emergency response to low blood pressure, near afferent arterioles


Say something about backward movement or reverse peristalsis at the cardiac oriface.

vomiting, rats cannot do it so they do not return to tastes that made them sick

What is the cause of stomach ulcer?

acid, bacterium Helicobacter pylori

What is the use of bicarbonate secretion from the pancreas?

neutralize acidy coming from stomach

"Salt and glucose facilitate the absorption of water across the intestinal epithelium." Under what circumstances would this knowledge allow you to save somebody's life?

give someone with Cholera Gatorade before EMS personnel come to hook up an IV

In a healthy person, urobilinogen is eliminated via the urine and (how else?).

in the feces

Facilitated by bile salts and catalyzed by lipase, triglyceride plus two water molecules is converted into (what three molecules?) in the intestinal lumen?

a monoglyceride plus two fatty acids

Obese mutant mice are deficient in leptin. Answer either (1) where (in a normal animal) leptin is made or (2) what part of the brain it affects.

adipose tissue, arcuate nucleus of hypothalamus

Why would it be useful for chief cells to have pepsinogen rather than pepsin in their secretory vesicles?

so it does not break down proteins until it is in the stomach

Proteins are broken into amino acids, and these are what move across the basolateral border of the intestinal epithelium. How does this differ for the apical surface?

di- and tri-peptides also move across the brush border

Why would a barbiturate have a stronger effect on a person who had not been taking barbiturates than on a person who had been taking barbiturates?

detoxifying enzymes in smooth ER (microsomal fraction) of liver cells are inducible

What, if any, type of polymer would be broken into monomers if given enough time in the presence of salivary amylase?


Chief cells: answer EITHER (1) What is the name of the zymogen (precursor) in the granules of these cells. (2) Acid secreted (from what cell?) helps to form the active enzyme from the precursor?

pepsinogen, parietal

A SEVERE stomach disorder was once attributed to excess stomach acid. A further elucidation of this disorder was worthy of the 2005 Nobel prize in medicine (awarded to Marshall and Warren). Answer either (1) What disorder? Or (2) What was the cause of the disorder they discovered?

ulcer, bacterium (Helicobacter pylori)

Enzyme activity as a function of pH: describe the graphs for pepsin vs. salivary amylase.

peaks are at 2 and 7 respectively

Say something about how or where trypsin is activated.

trypsin is activated in the intestinal lumen by chopping a fragment from the zymogen under the influence of enderokinase on the brush border (or by trypsin that has already been activated)

In reference to lipase in the intestinal lumen, tell me either (1) What is the source of lipase? Or (2) What are the products when it acts on a triglyceride?

pancreas, monoglyceride plus two fatty acids

Why is the function of the hepatic portal vein so important?

It delivers materials absorbed from the intestines to the liver for detoxification

Amino acids stimulate G cells to release gastrin. State one of the secretions that result from this.

One cell (ECL cell) puts out histamine causing parietal cell to put out HCl

Using the correct terminology about the drug's affect on appetite (hunger), tell me about amphetamine.

it is anorexogenic (it causes anorexia)

WARFarin: Answer EITHER (1) Why is a substance like this effective for poisoning rats when, otherwise, it is difficult to poison a rat? Or (2) Why might it be given, in lower than poisonous doses, to a person?
They will avoid the taste of something that makes them sick but the delayed anticoagulant action is not noticed (until it is too late), anticoagulants decrease the chance of a thrombus or an embolism
Absorption of what important substance from the gut is disrupted by cholera toxin?
Why is it useful to have a lot of mitosis in the crypts of intestinal villi?
Intestinal cells digest themselves and need to be replaced
"In digestion, we break proteins down into amino acids for absorption." How would you modify that statement for the apical membrane of intestinal epithelial cells.
Dipeptides and tripeptides also cross this membrane
Why is the function of the microsomal fraction of hepatocytes so important?
Detoxify drugs, alcohol, etc

Loss of what hormone would cause an adrenalectomized animal to crave salt?


What is the function of the "microsomal fraction" in liver cells?


Mitosis in the crypt of the villus is needed because of a short life expectancy of which cells?

intestinal epithelial cells

Repeated fatty metamorphosis of liver from alcohol binges leads to what scarring disorder?


In addition to facilitated diffusion at the basolateral cell surface, what is necessary for glucose transport in kidney tubule and intestinal cell? (Include process and location.)

apical cotransport with Na+

What hormone from adipose tissue contributes to weight regulation?


The opposite of dehydration synthesis (condensation reaction) happens in digestion. What is this called?


What is the optimum pH for pepsin?

very acidic (2)

Recycling of what kind of cell contributes to the dark color of feces, the yellow color of urine and the yellow skin in jaundice?

red blood cells

What is a zymogen?

inactive forms of digestive enzymes

Where does trypsinogen come from?


Cholera toxin affects the level of what famous "second messenger" in the intestinal epithelium?


The portal vessel in the digestive system connects the intestine (where absorption takes place) to that organ?

liver (its the hepatic portal vessel)

Jaundice is a symptom of a disorder of what organ?


What is the function of cholecystokinin (CCK)?

hormone in digestion, slows gastric emptying, cranks up pancreatic secretions

What is the function of salts of cholesterol made by the liver and secreted into the small intestine?

emulsify fats

In the intestine and the kidney tubule, three processes are needed for glucose transport, (1) basolateral sodium pump, (2) basolateral facilitated diffusion, and (3) apical... [your

glucose/sodium cotransporter

Cholera toxin interferes with water transport in the intestines in a mechanism utilizing what famous "second messenger?"


What is the name of the lymph vessel in the intestinal villus that is important if absorption of fat?


Many factors including hormones control gastric emptying via what "valve?"

pyloric sphincter

When I was in first grade, we were told to keep a saltine cracker in our mouth and notice that eventually it tasted sweet. What enzyme is responsible for this?


You swallow a bolus, and it gets broken apart and mixed with lots of fluid. What is the name of the fluid mixture emptying into the intestine?


What do you call the inclusions in pancreatic acinar cells with reference to the fact that they contain precursors of enzymes?

zymogen granules

What is the name biochemists use for the smooth endoplasmic reticulum of liver cells responsible for detoxifying toxins?

microsomal fraction

Where are the dipeptidases and tripeptidases responsible for the final breakdown of proteins to amino acids in digestion?

inside the intestinal cell

If one glucose transporter is on the brush border, where (specific cell surface) is the other?


In a healthy person, what is the fate of bilirubin after it arrives at the liver?

converted and out in feces

What is the source of the digestive enzyme that converts fats to fatty acids plus a monoglyceride?

lipase is from pancreas

What does it mean to say a substance is orexigenic?

makes you want to eat

Where is the median eminence?

Where hypothalamus connects to pituitary

Argue that the effect of a hypothalamic lesion on weight regulation might result from loss of affect by interrupting the nigrostriatal tract. Be specific about what effect you are talking about and/or what part of the hypothalamus.

weight loss from lateral hypothalamus lesion might be from not appreciatng the "goodness" of food

List one (of the several) effect of gastrin.

make parietal cell secrete HCl or chief cell secrete pepsinogen (or ECL cell secrete histamine)

Why is a portion of the hypothalamus referred to as "supraoptic?"

it is above optic chiasm

In what molecular form is fat absorbed from the intestinal cell (to the body)?

triglycerides combined with protein in droplet called chylomicron

Name an enzyme derived from a pancreatic precursor that is an endopeptidase.

trypsin, chymotrypsin

What are zymogen granules in pancreatic acinar cells?

contain precursors of digestive enzymes like trypsinogen

"Enterokinase on the brush border cleaves trypsinogen to activate trypsin." Translate.

the microvilli on intestinal epithelial cells activate the proteolytic enzyme by cutting off a peptide fragment

What is the purpose of bicarbonate secretion by the pancreas?

neutralize stomach acid for intestine

"Proteins are hydrolyzed into singal amino acids to be absorbed by intestinal epithelial cells and passed into the blood stream." Why is this not the whole truth?

peptides of 2 and 3 aminoacids can be taken into cell for final breakdown in cell

As heme is broken down, one of the products is bilirubin. What becomes of this substance?

conjugated to gluconuride, converted to uropilinogen, put out in feces and urine

The hepatic portal vein carries blood from the small intestine to where?


What happens to a monoglyceride inside a cell of the small intestine?

two fatty acids added (converted to fat (triglyceride)

Gastrin stimulates secretions of parietal and chief cells. Name these secrtetions.

HCl, pepsinogen

What would be the cause of death if you had cholera, and how might you prevent death if you were nowhere near medical help?

dehydration, gatorade

What specialization in the stomach regulates gastric emptying into the small intestine?

pyloric sphincter

"Leptin causes a decrease of the orexigenic neuropeptide Y from the arcuate nucleus." Translate.

neuropeptide Y from that part of the hypothalamus would cause the opposite of anorexia, so the protein leptin should be good for weight loss

Go on a drinking binge and there will be fat in the liver the next day. Biochemically, how did that fat get there?

alcohol -> aldehyde -> acetic acid (adds 2 carbons to a fatty acid)

The same sort of drug given to heart patients to decrease the likeliness of a thrombus is very useful as a rat or mouse poison. Why?

rats avoid tastes of foods that made them sick and anticoagulants work so slowly that they never make the association

Bilirubin results from what ativity in what organ?

derived from red blood cell hemoglobin, handled by liver

What molecules make up the chylomicrons that are transported to the lacteal?

triglycerides plus proteins

Why are ob/ob mice obese?

lack leptin

What is the word for the coordinated wave of smooth muscle contraction that propels a bolus of food forward through the esophagus?


Baking soda would be a quick fix for what digestive ailment?

"heartburn" caused by excessive stomach acid

The appropriate signalling that involves cAMP for water absorption in the intestine is disrupted by what toxin?


After enzymes act on proteins in the intestinal lumen, list every product of that degradation that gets absorbed into the intestinal cell.

single amino acids, dipeptides, tripeptides

Conversion to what molecule explains why alcohol consumption can cause fat deposits in the liver?

acetic acid (acetyl coA)

"Gastrin stimulates parietal cells to secrete HCl." In parallel, it stimulates chief cells to secrete what?


Why might the nigrostriatal dopamine tract have to do with hunger/satiety?

contributes to motivation and affect

What indication of body energy stores would cause leptin to increase?

increased fat in adipose tissue

"Agouti-related protein (AgRP) is orexigenic." Translate.

this protein, oddly related to coat color, increases desire to eat

"The product of the parietal cells activates the product of the chief cells." Elabortate.

parietal cell puts out acid which converts chief cell's pepsinogen into pepsin

Why do some people occasionally drink a spoonful of baking soda mixed in water?

baking soda = "bicarbonate of soda" = sodium bicarbonate, neutralizes stomach acid, helps with "heart" burn

Away from emergency responders, what can you offer better than water to rehydrate a cholera victim?

an electrolyte-glucose coctail such as Gatorade is absorbed better

The microvilli on the surface of the intestinal cells are so famous that they have a name. What is that name?

Brush border

Why, in terms of chemistry or process involved, does hepatitis lead to jaundice?

inflammation has hepatocytes spill bilirubin (from hemoglobin recycling) into blood instead of feces

In terms of fat digestion, what is transported across the basolateral surface of the intestinal epithelium into the lacteal?

chylomicrons are triglycerides bound to proteins

You were shown that amino acids stimulated the G cell to release gastrin which caused the production of (what?) (also where?).

(via an intermediate ECL cell that releases histamine): acid in the stomach

"Agouti-related peptide (AgRP) is orexigenic." Explain to someone who is not as sophisticated as you (are supposed to be) either: The meaning of orexigenic. Or. How (in the heck) did we get on the topic of agouti?

opposite of anorexigenic, stimulating appetite. Although agouti has to do with coat color, this protein which is orexigenic is like agouti, hence that seemingly esoteric naming

For glucose absorption from the gut, what is the process on the basolateral surface that requires energy?

The sodium pump

Sometimes endopeptidases will cut off fragments that are two amino acids long. What becomes of these?

"In histology, you see zymogens located in acinar cells." What does that have to do with digestion?

These granules house the precursors of digestive enzymes of the pancreas

Relate the hepatic portal vessel with the "microsomal fraction" (smooth endoplasmic reticulum of the hepatocyte).

This gives the liver a chance to detoxify what is absorbed from the gut before it gets to the systemic circulation

"A lesion in the lateral hypothalamus (LH) gives you a thin rat, hence the LH is a hunger center." What have we learned since this conclusion was first reached that gives us a different view of the role of the LH?

The LH has the dopamine tract that is useful in motivation (affect) in general

Make an argument that salivary amylase is not of significant value in the overall hydrolysis of macromolecules for digestion.

swallow soon and inactivated in stomach

At what structure is gastric emptying controlled.

pyloric sphincter

"Proteins are broken down into amino acids and that is what is absorbed." Why is this not the whole truth regarding the apical surface of the intestinal epithelial cell?

uptake of di and tri peptides

Why is jaundice one sign of hepatitis?

b/c bile pigments build up in blood

"Everybody knows about (what structure that feeds blood from the small intestine to the liver?) if they took a course like this."

hepatic portal vein

What are the products when lipase acts on triglyceride in the lumen of the small intestine?

2 fatty acids and monoacyl glycerol

With the G cell, the ECL cell, histamine, amino acids, and the vagus nerve, answer either (1) What hormonal system?, (2) That hormone affects what cell type? Or (3) That cell type releases what?

gastrin, parietal, HCl

Homozygous obese (ob/ob) &shyp; Answer either (1) What is the protein product of that gene that is missing? Or (2) What tissue releases this product (in non-mutant mice)?

leptin adipose

Why would it be useful to have the proteolytic enzymes in digestion stored as inactive precursors in the granules (zymogens) in the cells that secrete them?

so enzymes do not digest their granules and cells

Why are enzymes on the brush border important for trypsin function?

they convert trypsinogen to trypsin

Heme is broken down to iron, carbon monoxide and (fill in the blank). (OK if you say the immediate product or subsequent steps in the processing of this product.)

biliverdin, bilirubin, bilirubin glucuronide (conjugated bilirubin)

To bring fats into the lacteal, what, in fact, is transported across the basolateral membrane of the intestinal epithelium cell?

chylomicrons (tryglycerides and proteins)

Why was it relevant to remind you about Parkinson's disease after saying that lesions of the lateral hypothalamus caused the rat to lose weight?

lesions would interrupt nigrostriatal dopamine tract causing loss of affect


Why would we refer to oxytocin as a "neurosecretion" but not ACTH?

oxytocin comes from nerve cells of the hypothalamus, ACTH from endocrine cells of the anterior pituitary

Answer one of the following: Releasing hormones are produced by (what structure?) and have their effect on (what structure?) after being carried by (what conduit?).

hypothalamus, anterior pituitary, portal vessel

Under the influence of growth hormone, bones get longer while you are growing. How does growth hormone affect bones after you are full grown?

acromegaly, they get thicker

Glucocorticoids - answer either - (1) are produced where? (be specific) or (2) feed back to the anterior pituitary to inhibit the release of (what hormone?).

adrenal cortex (ok if you wrote zona fasciculata and reticularis), ACTH

Steroids of the ovary are secreted by what specific portion(s) of the ovary?

follicle, corpus luteum

Fertility is blocked by the pill...answer one of these: (1) How is fertility blocked? or (2) Why would there still be menstruation every month?

no ovulation (b/c no LH or FSH [b/c of steroids in the pill]), steroids build up endometrium, then lack of steroids let it break down

Why would a couple only need to abstain from intercourse for a few days per month to avoid pregnancy?

egg only present and viability are limited as is the viability of sperm delivered near the time when the egg is present up in the uterine tube

Something the size of the fertilized egg, but further developed, implants into the receptive endometrium. A portion develops into an endocrine-secreting tissue. Answer either (1) What is the function of the hormone it produces? or (2) What is the chemical nature of the hormone it produces?

maintain the corpus luteum, peptide

Vitamin D has effects more similar to (which?) calcitonin or parathormone. Explain (justify).

increase blood calcium like parathormone

An osteoclast contributes to the regulation of blood calcium ... Answer either (1) under the influence of what hormone? (2) how?

parathormone, secrete HCl to break down calcium phosphate and enzyme to break down collagen

The synthesis of 1,25-Dihydroxyvitamin D3 from 7-Dehydrocholesterol involves kidney, liver, and (what other organ?).


With respect to its effects in the breast and in the uterus, what type of cell is affected by oxytocin?

smooth muscle

If iodine is adequate, thyroid hormones (T3 and T4) feed back to the anterior pituitary to inhibit the release of (what hormone?).


A surge of LH leads to what changes in the ovary? (There are two answers but you need provide only one.)

ovulation, conversion of the follicle to the corpus luteum

There is a new hormone after implantation, and it is a good one to assay to test for pregnancy. What is that hormone?


Calcium-regulating hormones regulate blood levels of calcium ions at three sites, bone, intestine, and (where else?).


The kidney and the liver are two of the three organs used to make 1,25-Dihydrovitamin D3. What is the third organ?
A gland in the neck puts out a hormone that inhibits the dissolution of CaPO4 from bone. Name EITHER (1) the gland or (2) the hormone.
Thyroid, calcitonin
What are the gonadotropins for spermatogenesis and testosterone secretion?
Why is an enzyme (as well as acid) a useful secretion of an osteoclast?
Digest the collagen that the calcium phosphate was embedded in
In its effects in the mammary gland and uterus, what kind of cell is affected by oxytocin?

smooth muscle

If a body builder abuses growth hormone, what is likely to happen to his or her bones?

they will grow in thickness

What is a general term that takes into account the trophic influence for both males and females of FSH, LH, ICSH and HCG?


What happens if there is too little thyroid hormone during an infant's development?

brain development is compromised (cretinism)

"The follicle includes a 'rind' of cells and the egg enclosed in this rind." What does this rind do?

secretes estrogen

"There is a surge of LH." Answer one (1) Where did this LH come from? (2) What kind of molecule is that LH? Or (3) Name one of the effects that has on the ovary.

pituitary, peptide, convert flooicle to corpus luteum, cause ovulation

Would the endometrium build up and break down in women who are taking the pill? (Include in your answer why or why not.)

yes, steroids would cause build up and duds (without steroids) would allow break down

What happens to the corpus luteum after implantation?

It is maintained and continues to secrete progesterone under the influence of HCG

What kind of molecules, biochemically, are the hormones released by the posterior pituitary?
One capillary net is in the infundibulum and receives its hormones as neurosecretions from the paraventricular and preoptic areas of the hypothalamus. Obviously, I am describing a portal system. Where is the second capillary net?
Anterior pituitary
Why did former President Kennedy seem to have a nice sun tan?
With low cortisol from Addisons disease, little feedback resulted in too much ACTH which overlaps with MSH (melanocyte SH)
Would the corpus luteum build up and break down in women who are taking the pill? (Include in your answer why or why not.)
no b/c steroids of the pill inhibit FSH and LH which would build follicle into corpus luteum
A gland in the neck puts out a hormone that causes the dissolution of CaPO4 from bone to increase blood calcium. Name EITHER (1) the gland, (2) the hormone, or (3) the cell that mediates dissolution of the bone.
Parathyroid, parathyroid hormone, osteoclast
What is the hormone from the adrenal medulla?
Epinephrine (adrenalin)
What is the function of a signal known as "inhibin?"
feedback on FSHs effectiveness on seminiferous tubules
Loss of what hormone would cause an adrenalectomized animal to crave salt?


What is the name of the disorder of too much growth hormone as an adult?


Vitamin D helps to keep the blood levels of what substance correct?


Historically, shortage of what mineral caused some inland people to develop goiter?


Why are alcoholic beverages contraindicated to stay hydrated in times of heat stress? (Make sure your answer says what happens to the relevant hormone level.)

alcohol inhibits ADH, more water is lost through kidney

After ovulation, the estrogen secreting follicle turns into a tissue that secretes what hormone?


In the process where epinephrine causes glucose release from liver, what enzyme does cAMP activate?

protein kinase A

What kind of chemical is a gonadotropin?


The birth control pill feeds back to inhibit what pituitary peptide (to prevent maturation of the follicle)?


What does the osteoclast do to assist in Ca2+ homeostasis?

cause bone to release Ca2+

What pituitary hormone maintains the cells that secrete testosterone?


Within the ovary, what tissue produces estrogen?


Why is the term "anabolic" applied to some hormones?

growth (muscles, bone, hemoglobin)

Where are the cell bodies of the cells whose axon terminals release ADH and oxytocin?


ACTH triggers the release of what hormone from its target gland?


What is the tissue responsible for producing the gonadotropin that supports the corpus luteum early in pregnancy?


Why is such a small amount of thyrotropin-releasing hormone TRH needed?

because portal system delivers straight to anterior pituitary

Although dopamine is a transmitter itself, it can be converted into what other neurotransmitter by the enzyme dopamine beta-hydroxylase?


What hormone would put calcium back into bones?


A surge of what peptide leads to ovulation?


What second messenger activates protein kinase when the beta-adrenergic receptor of a liver cell binds epinephrine?


What would happen to the TSH level if dietary iodine were deficient?

go up since negative feedback from thyroxine is decreased

What cleavage product of pro-opiomelanocortin would be high in Addison's disease?


How would calcitonin regulate Ca2+ at the level of the kidney?

decrease resorption

In the term "gonadotropin," what does the suffix "tropin" refer to?

has trophic effect

What would happen instead of increase in bone length if growth hormone were too high in the adult?

bones would get thicker

In the old days, what would cod liver oil be used for?

vitamin D (and A) replacement

In the pathway 7-dehydrocholesterol -> vitamin D3 -> 25-hydroxyvitamin D3 ->1,25-dihydroxyvitamin D3, where does the first conversion take place?

in the skin

Osteoclasts contribute to the breakdown of CaPO4 plus what additional component, a protein, in bone?


A surge of LH mediates ovulation plus the conversion of the follicle into what tissue?

corpus luteum

What is it called when, because of low progesterone, the endometrium is no longer supported?


What hormone supports the endometrium during pregnancy?


What effect does calcitonin have on the kidney?

Allows for CaPO4 loss in urine

What type of chemical is the product of the Leydig (interstitial) cells?


Chemically, what type of molecule is a gonadotropin?


What would be the most common reason to administer oxytocin (or a synthetic version of this hormone)?

induce labor

Why would very small amounts of TRH be needed for adequate homeostatic control?

portal vessel from hypothalamus to pituitary means that it is not diluted by the systemic circulation

Although steroids in the birth control pill would have a trophic effect, building up the endometrium, they block pregnancy. By what mechanism?

by inhibiting FSH and LH, they prevent ovulation

What is the effect of the hormone of the adrenal medulla on heart rate?

adrenalin increases heart rate, of course

A lot of hormone from the parathyroid gland would decrease calcium in what notable reservoir in the body?


Ovulation, as well as the conversion of the follicle to the corpus luteum, is induced by a surge in what pituitary peptide?


PTH, the hormone of the parathyroid, acts on the kidney to stimulate Ca2+ reabsorption and inhibit PO4- reabsorption. What other effect does PTH have on kidney to help to increase plasma Ca2+?

formation of 1,25-dihydroxyvitamin D3 (increase 1alpha-hydroxylase activity

Who would suffer from acromegaly?

adults with too much growth hormone

Why would your skin be dark if you had Addison's disease (inadequate cortisol, no feedback, too much ACTH)?

ACTH mimics melanocyte stimulating hormone

Chemically, what type of hormones are the hormones of the adrenal cortex?


If estrogen and progesterone maintain the endometrium, how come women taking the birth control pill still have menstruation?

estrogen and progesterone are not given for a few days

Why is the term "neurosecretion" used for some hormones and give one example.

neurons with axons release chemicals from their terminals near blood vessels, ADH, oxytocin, releasing hormones

What happens if there is too much growth hormone in the fully-grown adult?

bones grow in thickness, not length, acromegaly

What leads to hypertrophy of the thyroid gland (goiter)?

deficiency of iodine

Why do they need to build fish ladders beside tall dams?

salmon go up their native stream to spawn

What type of chemical is the hormone secreted by the follicle?


After implantation, what peptide stimulates the corpus luteum to continue progesterone secretion?

human chorionic gonadotropin

What important cell, other than the hormone-secreting cells, is present in the follicle?

the egg

What type of chemical is the hormone that has a trophic effect, causing the Leydig cells (interstitial cells) to release their hormone?


H2CO3 is split in osteoclasts. Where do the two portions go and why?

H+ for acidity into bone on one side of the osteoclast, HCO3- exchange with Cl- on the other side to start Cl- toward the bone to make HCl

Which hormone from a gland inside the neck has the same effect on plasma calcium ion concentration as 1,25-dihydroxyvitaminD3?


Why might you want to inhibit the normal function of osteoclasts?

to stave off osteoporosis

ACTH is cleaved from what peptide precursor?


What organ are the steroid-secreting zona fasciculate and zona reticularis part of?

adrenal cortex

Out of a long laundry list, tell me one precursor of the hormone from the adrenal medulla.

tyrosine, l-DOPA, dopamine, norepnephrine

What is it called when a hypothyroid condition as an infant leads to deficient neural development?


What is the condition where there is too much ACTH? - Answer one: (1) name of condition (2) What is there too little of? Or (3) Why does the skin get dark?

Addison's disease, too little cortisol, ACTH is like MSH (melanocyte stimulating hormone)

The adrenal cortex is famous for producing androgens, glucocorticoids and (what else?).

mineralocorticoids (aldosterone)

Norepinephrine is converted to epinephrine to be the major hormone of what (specific) gland.

Adrenal medulla

Why would cod liver oil be a useful dietary supplement for some people?

Vitamin D

Address the terms "paraventricular" and "supraoptic" in ONE of the following ways: (1) What part of the brain are they in? (2) How did those nuclei get those names? (3) What structure is the output of this neurosecretion? Or (4) What are the hormones?

hypothalamus, around the (third) ventricle and above the optic chiasm, posterior pituitary, ADH or oxytocin

For one portal system, the first capillary bed is in the pituitary stalk. Answer ONE of these (1) Where are the cell bodies responsible for secretion into this vascular bed? Or (2) Where (specifically) is the second capillary bed?

hypothalamus, anterior pituitary

Distinguish between what happens with too much growth hormone as a child vs as an adult.

become a giant, acromegaly

How come women who took the birth control pill still menstruated?

out of the 28 days, the steroids are not in the last 5 days so the endometrium is not supported

What are the two different functions of the pituitary gonadotropins in the male?

FSH spermatogenesis, LH getting the interstitial cells of Leydig to secrete testosterone

A surge in LH converts the follicle to the corpus luteum and (what else does it achieve?).

causes ovulation

Why doesn't the endometrium break down once FSH and LH stop maintaining the corpus luteum when implantation has occurred?

HCG supports the corpus luteum, so there is still progesterone

Starting with 7-Dehydrocholesterol, what is the order of action of the 3 separate ORGANS in the production of the active form of vitamin D?

skin, liver, kidney

A hormone from the thyroid has (what effect on the kidney?) for calcium homeostasis.

calcitonin stimulates excretion of Ca2+

"If the mother plans to breast feed, it is useful to give her the baby to suckle right after delivery" for what endocrine reason?

to retract uterus

In what way would growth be different if there were too much growth hormone as a child vs. too much growth hormone as an adult?

bones get longer vs thicker

In addition to its negative feedback control on the hypothalamus/pituitary, what effect does estrogen have on the endometrium?

build up

"The pill"; one a day for 28 days: Why would women still menstruate?

estrogens - build up of endometrium, duds, let it break down

In addition to triggering ovulation, a surge of LH does what (to the endocrine structure/function of the ovary)?

follicle changes to corpus luteum

Once human chorionic gonadotropin "takes over," what is the status of FSH and LH release by the pituitary?

they are still not released, inhibited by progesterone

Once human chorionic gonadotropin "takes over," what is the status of FSH and LH release by the pituitary?

progesterone from the still functioning corpus luteum still inhibits Pituitary FSH and LH

In the old days, some people would have had rickets. What aspect of their life style (discounting diet) would have led them to have gotten this disorder while other people would not?

winter, clothing, sun avoidance

Zona facicularis and zona reticularis put out what hormone in addition to glucocorticoids?


What allows FSH to be released at the "beginning" of the cycle?

lack of inhibition because of lack of estrogen and progesterone

Why would osteoporosis become more of a potential problem after menopause?

lack of estrogen (which would have helped osteoblasts build bone calcium)

Several organs are involved in bioconversions of various molecules that have the words "vitamin D." What is the original precursor of all the vitamin D forms?



Progesterone is not only a hormone of its own right, it is also the precursor of (list one of the three important hormones plus the organ that the hormone you choose is made.

testosterone leydig cells (interstitial cells) of testes, cortisol (hydrocortisone) adrenal cortex, estradiol 17 beta follicles of ovary

What effect if any would castration have on the seminal vesicle?

it would be smaller

Upstream of a gene, there is a place where a steroid protein receptor combined with a steroid hormone binds. What is this area in the DNA called?

a response element

In a rare syndrome, a chromosomally normal female can be masculinized by androgens. Considering that she does not have testes, where did these androgens come from?

adrenal cortex

The enzyme 5-alpha-reductase is thought to be involved in androgenic alopecia. Answer either (1) What is androgenic alopecia? or (2) What product of 5-alpha reductase might contribute to androgenic alopecia?

baldness in men, dihydrotestosterone

The hormone T4 comes up to a cell's plasmalemma in the company of a carrier protein. Say something about what else is involved before that hormone might activate a gene's transcription.

converts to T3, binds receptor protein, that protein binds DNA, in the company of 9-cis retinoic acid bound to RXR receptor

Answer one of the following: COX-2 inhibitors were greeted with enthusiasm by medical professionals and patients at first (why?) but eventually there were problems (why?).

without also inhibiting COX1, there were fewer gastric problems, but, alas, the incidence of heart attacks increased

Say something about why estrogen replacement therapy for the prevention of osteoporosis is not universally advised.

increase breast cancer, heart attack and stroke

Lipoxygenase and cyclooxygenase are enzymes that (answer one of the following) (1) act on what precursor? or (2) make what two general classes of products respectively?

arachidonic acid (20:4), leukotrienes and prostaglandins

What female hormone is a precursor of testosterone?
What are the gonadotropins for spermatogenesis and testosterone secretion?
Triiodothyroxine binds to a receptor that binds to the half site of a response element. What binds to the receptor that occupies the other half of the response element?
Retinoic acid
Androgens come from the testes and (where else?).
adrenal cortex
5alpha-reductase is required for normal function because it makes (what?) out of (what?) [answer both].
DHT from testosterone
Why were COX-2 inhibitors initially considered to be an important advancement beyond drugs like ibuprofen in the treatment of arthritis?
Since they did not inhibit COX-1, they helped in arthritis treatment without gastric side-effects

Why would a transdermal patch be better than oral administration for estrogen replacement therapy?
Less conversion by liver
A steroid hormone binds to a receptor that is located in the cytoplasm of the cell. State one of the next things that happens with this hormone-receptor complex.
Goes to the nucleus and binds response element, a place in the promoter on DNA
What does "20:4" signify when referring to the precursor of prostaglandin?
Arachidonic acid, a fairly long chain fatty acid, is 20 carbons long and has 4 double bonds
On what kind of molecule would you find a sequence known as a "hormone response element (HRE)?"


Non-steroidal antiinflammatory drugs (NSAIDs) block converrsion of what fatty acid to prostaglandins?


In the process where epinephrine causes glucose release from liver, what enzyme does cAMP activate?

protein kinase A

A receptor (protein) for T3 makes a heterodimer with a receptor for what substance?

retinoic acid

Hyperplasia of what gland would androgenize a female?


What syndrome results from 5a-reductase deficiency?

testes at twelve

What treatment has been standard for relief of hot flashes?

estrogen replacement therapy

Name one molecule in the biosynthetic pathway between cholesterol and testosterone.


To mediate many of the effects of testosterone, aromatase converts it to what?


After the alpha subunit of the heterotrimeric G protein binds GTP, what does it do to GTP?

breaks it to GDP (and P)

What close relative of retinal (retinene, the part of rhodopsin that absorbs light) is important in the activation of the hormone response element by triiodothyroxine?

retinoic acid

What second messenger activates protein kinase when the beta-adrenergic receptor of a liver cell binds epinephrine?


Increased testosterone at puberty affect what organ to turn sopranos into altos?


Testosterone is converted to dihydrotestosterone (DHT) by what enzyme?


Tamoxifen used to be called an antiestrogen but might now be better referred to as a SERM (selective estrogen receptor modulator). Why?

antagonist in some tissues but agonist in others

A heterodimer of receptors for thyroid hormone and retinoic acid (together with their respective ligands, thyroid hormone and retinoic acid) binds to what specific location on what molecule?

response element on DNA

Estradiol-17b is made by aromatase from what steroid (the immediate precursor)?


Give a reason why the exact same mixture of hormones might have different effects in a woman if given orally vs via a transdermal patch.

would go to liver by hepatic portal vessel if taken by mouth

A steroid hormone receptor is famous for binding the hormone as well as what major macromolecule?


Give the name of a class of molecules produced by enzymes acting on arachidonic acid (20:4).

prostaglandins (leukotrienes)

In terms of how they inhibit prostaglandin synthesis, how would a COX2 inhibitor differ from traditional NSAIDS like aspirin?

aspirin was non-specific (COX1 & 2)

Where is the receptor for steroid hormones?

inside the cell

formation of 1,25-dihydroxyvitamin D3 (increase 1alpha-hydroxylase activity

What famous steroid hormone is an intermediate in the conversion of progesterone to estradiol-17beta?

testosterone (also androstenedione)

A DNA-binding domain is a hallmark of what kind of molecule that binds to a hormone response element?

steroid hormone receptor protein

Testosterone is converted by 5alpha-reductase or by aromatase into (name one of these steroids)?

dihydrotestosterone, estradiol-17beta

How does cAMP activate the kinase?

binds to and removes inhibitory subunit from catalytic subunit

Answer one of the following for the precursor that cyclooxygenase turns to prostaglandins and lipoxygenase turns into leukotrienes - (1) name it, or (2) say what kind of molecule it is, or (3) where does it come from?

arachidonic acid ((20:4), fatty acid, from membrane phospholipid

Why would hyperplasia of the adrenal masculinize a female?

adrenal cortex makes anabolic steroids like testosterone, too much if there is hyperplasia

Why is the area upstream of a gene's coding sequence relevant to the actions of retinoic acid, thyroxine and steroid hormones?

this area is the promoter where steroid hormone receptors , retinoic acid receptors, etc bind

The G protein coupled receptor signals to the next molecule in the cascade, namely the G protein. Why is it called a G protein?

binds GTP

Describe why the system of the hepatic portal vessel might be relevant in estrogen replacement therapy.

Any chemicals, if taken orally, might be converted to other things by the liver

Testosterone gets converted to other steroids for its activity. Tell me one of the enzymes that effects these conversions.

5-alpha reductase (to 5 alpha DHT) or aromatase (to estradiol-17beta

One part of the retinoid X receptor (RXR) binds 9-cis retinoic acid. What does the other part of this molecule bind?

DNA (the RARE)

Why doesn't the alpha subunit of the heterotrimeric G protein activate the adenylate cyclase indefinitely?

it has GTPase activity (etc.)

Why would a selective estrogen receptor modulator (SERM) be so potentially useful for bone health?

have the beneficial effect on osteoblasts but not promote breast cancer or cardiovascular problems

Many hormone receptors are on the cell membrane. How can steroid hormone receptors work when they are inside the cell?

by binding steroid hormones and also binding DNA at hormone response element

Tell me one of several molecules that are precursors for all of these: hydrocortisone, testosterone, and estradiol-17beta.

cholesterol, pregnenolone, progesterone

"A gene is the coding sequence for a protein." The truth but not the whole truth. Relative to this, where is the hormone response element?

upstream of the coding sequence

What is the precursor of leukotrienes, and where (in the cell's anatomy) does it come from?

arachidonic acid, in membrane lipid

Why did COX-2 inhibitors show so much promise, and why were some pulled from the market?

reliece arthritic inflammation without interfering with gastric mucosa, increased chance of heart attack

By what mechanism is estrogen good for bones?

it promotes osteoblasts

Why was there the conventional wisdom that estrogen by patch was safer than oral administration?

Swallowed, the liver could make many other products

Why was the women's health initiative study discontinued?

Increase in breast cancer, coronary heart disease

For "androgenic alopecia" tell me either (1) what these words mean, or (2) what an enzyme or the hormonal product it catalyses has to do with that.

Male pattern baldness, 5 alpha reductase makes DHT

Progesterone is the precursor of what two sex steroids?

testosterone and estradiol

Where, specifically, is the hormone response element?

on the DNA upstream of the coding sequence for the protein

Why would a mutation in the receptor that caused insensitivity to androgens have the effect it has in androgen insensitivity syndrome?

testicular feminization b/c there is no response to hormones like testosterone

Why at the time, was the availability of new COX-2 inhibitors heralded as such an important development?

arthritis symptoms taken care of without the COX-1 interference with the gastric mucosa

The thyroid receptor makes a heterodimer with a receptor for what signaling molecule?

retinoic acid

Estrogen and thyrocalcitonin (calcitonin) would affect bone, answer either (1) With what cell type? Or (2) In what way (would they affect bone)?

osteoblasts, put in calcium

Name a precursor of estradiol-17b.

testosterone, progesterone, cholesterol

"Steroid hormones affect transcription of certain genes. How?

bind receptor protein that binds response element

They used to call Tamoxifen an anti-estrogen, now they call it a SERM. Answer either (1) How does SERM translate? Or (2) Why the change?

selective estrogen receptor modulator, it affects different tissues differently

Just like T4 is converted to T3 for receptor activation, testosterone is converted. Name (1) one of the two active products of testosterone OR (2) one of the two enzymes used to make these products from the precursor (testosterone).

dihydrotestosterone (5alpha-reductase) estradiol-17beta (aromatase)

For the precursor of prostaglandins, answer either (1) How many carbons long? Or (2) How many double bonds?


Why was there such enthusiasm for Vioxx and Bextra and why were they eventually pulled?

by selectively blocking COX-2, arthritis could be selectively dosed without inhibiting COX in the gastric mucosa, thee was increase in heart attacks

Why would osteoporosis become more of a potential problem after menopause?

lack of estrogen (which would have helped osteoblasts build bone calcium)

While estrogen replacement therapy was still widely accepted, the conventional wisdom was that the transdermal patch was better than oral administration. What is wrong (with oral administration), assuming the same hormone is in each.

hepatic portal vein delivers absorbed hormone liver that converts it to lord knows what

What partners with the T3 (triiodothyroxine) receptor to activate the response element?

the retinoic acid receptor


A blood test to assay for (name the substance in words) is commonly used to determine the likelihood of prostate cancer.

prostate specific antigen

In the ovary, if the corpus luteum becomes the corpus albicans, what does that signify?

didn't get pregnant, no gonadotropins

After the zygote is first formed, but before implantation, some rudimentary development occurs. Answer either (1) What is the term used for these cell divisions? or (2) Where do they take place?

cleavage, uterine (fallopian) tube

Why did they need a surrogate mother when they cloned Dolly?

after nuclear transfer in vitro and early development, they neded a uterus to implant into

In early development, what happens to the Mesonephric duct in the absence of testosterone?

it degenerates instead of becoming the epididymis, vas deferens, etc

Testes, prostate, bulbourethral gland (Cowper's gland). What gland that is missing from that list contributes to semen?

seminal vesicle

I said "The likelihood of having two sperm cells with the same combination of genes you got from your mother vs. your father in your whole life is infinitesimal." State how this diversity is achieved,

not only is there a random selection of which centromere is chosen (that comes to 2 to the 23 possibilities) but crossing over (recombination) exchanges genes along the chromosome

Answer one of the following. (1) What is the status of the "egg," in terms of progress through the entire process of meiosis, at the time of ovulation? or (2) What is the status of the "egg," in terms of progress through the entire process of meiosis, at the time the sperm is about to penetrate?

same answer for both. Through with meiosis I but not II (arrested at metaphase)

After implantation,...(answer ONE of the following) a peptide ([1] name that peptide) sees to it that a steroid ([2] where is the steroid from?) maintains the endometrium.

HCG, corpus luteum

"The IUD does not prevent fertilization!" Elaborate.

after fertilization and early development, it prevents implantation.

In 2006, while George W. Bush was President, the famous actor Michael J. Fox, who has Parkinson's disease, came to Missouri to support McCaskill, the democrat running for senate. Answer either (1) Why would he have been so interested (in embryonic stem cell research)? or (2) Why has interest in the issue of embryonic stem cell research decreased so much since then?

such stem cells might eventually be used in treatments to replace the degenerated neurons but now embryos might not be needed since skin cells can be made into pluripotent stem cells

About the time chorionic villi are present, what had been the inner cell mass has further developed, and one portion is now called the embryo. Answer either (1) Why might it be useful to biopsy the chorionic villi? or (2) In addition to the endoderm and the mesoderm, what is the third layer in that early embryo?

to test for chromosomal or genetic disorders, ectoderm

What happens if there is no Mullerian inhibiting factor?

uterus and uterine tubes are formed

Spermatids become spermatozoa. State one of the things that occurs during this process.
Cells become separated, cytoplasm is sloughed off and flagella are added
How is sperm moved along the length of the ductus (vas) deferens?
Peristalsis by smooth muscle
In addition to sperm from the testes, several glandular secretions contribute to semen. Name one of the glands.
Prostate, seminal vesicle and bulbourethral (Cowpers) gland
Simultaneous with menstruation, what happens to the corpus luteum?
It regresses (becomes corpus albicans)
"It is the conventional wisdom that men are more likely to have erections when they are asleep." Explain why this is the case in physiological terms.
High parasympathetic output
In your textbook's diagram of the seminiferous tubule, cells called "spermatogonia" were shown. No analogous "oogonia" were shown in the diagrams of the ovary. Why not?
There are no oogonia after 3 months of age
At what stage in the process of meiosis is the egg at the time of ovulation?
It is a secondary oocyte and has not completed the second meiotic division
"Then it implants into the endometrium." EITHER (1) name or (2) describe what it is that implants.
Blastocyst, ball of cells with inner cell mass, trophoblast and blastocyst cavity
What capability did embryonic stem cells possess that other cells lacked?
Pluripotent or totipotent, can become any type of cells
Explain why it is safe to assume that cells from the amniotic fluid do not come from the mother.
Amnion is on one side, embryo then fetus, on the other and everything is surrounded by chorion, all derived from zygote
Under the influence of a gene on the Y chromosome, "indifferent gonads" turn into a structure that produces Mullerian Inhibiting Factor (MIF) plus (what?).
the testes also produce testosterone
Answer EITHER: "Viagra inhibits the enzyme (what enzyme?) that breaks down (what?) as a medication for erectile dysfunction."
Phosphodiesterase, cGMP
How much before or after the sperm meets the egg is meiosis completed for the egg?
Pretty much simultaneous (just a moment before) fertilization
What would have happened to a person who did not have Mullerian Inhibiting Factor (MIF)?
Primordial "plumbing" would become uterus and uterine tubules
How many oogonia does a woman have at puberty?


A ball consisting of trophoblast plus what other clump of cells becomes implanted in the endometrium?

inner cell mass

When is meiosis completed in the "egg?"

when sperm meets egg

A low PSA reading is around 1 while a high PSA is 5. What does PSA stand for?

prostate specific antigen

Where is the acrosome?

tip of spermatozoan

Why might a physician want to test a sample of amnionic fluid?

to test prenatally for gene or chromosomal defects

Semen has components from seminiferous tubules, seminal vesicles, bulbourethral (Cowper's) gland, and what other gland?


The trophoblast becomes the chorion, and the chorion, in turn, becomes what?


What divides to make monozygotic (identical) twins?

inner cell mass

Where does fertilization take place?

way up in uterine (Fallopian) tube

What becomes of the mitochondria of the spermatozoan during fertilization?

they do not go into the egg

Incontinence is a common consequence of what surgery?


What is the result of ligating and snipping the vas deferens?

man is no longer fertile

Where is the "egg" when meiosis is complete?

when the sperm fuses

What divides to make identical twins?

inner cell mass

Genetically, how are fully differented adult cells different from pluripotent stem cells?

They both have the same genes, though only a limited subset are being expressed in the former

One diploid primary oocyte undergoes two meitic divisions. How many cells that can be fertilized result?

only one

What part of the blastocyst will eventually (much later) become the placenta?


How can a physician test for defects earlier than amniocentesis?

chorionic villus biopsy

What happens if neither MIF (Mullerian inhibition factor) nor testosterone are present?

primordia of sex structures adopt female development

The PSA (prostate specific antigen) test is used to diagnose a predisposition for what disorder?

prostate cancer

Why is development of uterus and clitoris considered the default pathway?

testes-determining factor (TDF), Mulleriasn-inhibiting factor and testosterone actively cause indifferent gonad primordia to select the male pattern

Spermatogonia undergo meiosis to make sperm. In what way is this process different for formation of oocytes in the adult human?

There come to be no oogonia in women, thus the entire meiosis does no occur throughout life, way fewer gametes are formed, 4 sperm vs 1 oocyte and polar bodies, sperm constant oocyte meiosis regulated when sperm meets egg

Name one of the glands that adds to sperm to make semen.

bulbourethral (Cowper's), seminal vesicle, prostate

Nitric oxide activates an enzyme that makes cGMP. (Maybe you did not know this.) Why might some people take a drug to inhibit the enzyme that breaks down cGMP?

for erectile dysfunction

Why is the IUD (intrauterine device) particularly controversial?

prevents implantation, not fertilization

Say where (or when) the second meiotic division occurs for the oocyte

uterine tubule, when sperm meets egg

What technique provides earlier information on genetic or chromosomal abnormalities than amniocentesis?

chorionic villus biopsy

What specific body of cells divides to make monozygotic (identical) twins (and also is a source of embryonic stem cells)?

inner cell mass

What is the "egg" called officially at the time of ovulation, and what stage of meiosis or mitosis is it at at that time?

secondary oocyte, before meiosis II is complete

Tell me about oogonia in the human female between the first menstrual period and menopause.

there are none

Why do proponents think that embryonic stem cells might be useful to treat Parkinson's disease.

such cells are pleuripotent

An embryonic structure becomes the penis if testosterone is present. What does it become without testosterone?


Tell me about spermatogonia in the adult male.

diploid, replace themselves by mitoses, give rise to diploid primary spermatocytes

Ligation and cutting of what tube is a common elective surgery for men to achieve sterility?

vas deferens

Why might an elderly man decide not to have surgery after first being diagnosed with prostate cancer?

it progresses slowly, surgery has side effects

Ovulation comes after a striking surge in what gonadotropin from where?

LH from anterior pituitary

Where (anatomically) does fertilization take place in the human.

in the uterine (fallopian) tube

How do dizygotic (fraternal) twins come about?

2 ovulations

Birth control prevents fertilization. Why is the intrauterine device qualitatively different?

prevents implantation meaning that fertilization (and many cell divisions) have already taken place

In cloning (Dolly, for example) what do you put into the surrogate mother and where?

blastocyst to uterus

"Spermatogenesis: the formation of spermatozoa, including meiosis" (from the glossary in your book). How is spermiogenesis distinguished from spermatogenesis?

spermiogenesis is just the stripping of the cytoplasm of spermatids and the streamlining of spermatozoa

For purposes of family planning, some men elect to have a straightforward surgery that results in sterilization. What is done?

vasectomy = ligate and sever the vas deferens

Why might an elderly man decide not to have surgery for prostate cancer?

it is a slowly developing cancer, and possible side effects of impotence and incontinence detract from the quality of life

As the sperm cell is about to fertilize the "egg," how far along in its meiotic divisions is the egg?

arrested at metaphase II (i.e. meiosis I is complete, but not II)

When are primary oocytes formed from oogonia in the human female?

before birth

With the intrauterine device, which irritates the uterus, the likelihood of an ectopic pregnancy is increased. How does ectopic differ from normal?

way up in uterine (fallopian) tube (instead of uterus)

What is the specific source of embryonic stem cells?

inner cell mass

What is the difference between identical vs fraternal twins in how they are formed?

two ovulations both fertilized fraternal, inner cell mass divides identical

Why do researchers have high hopes for the use of embryonic stem cells for eventual therapies for disorders like retinal degeneration and Parkinson's disease?

they are pluriotent, amazingly form into needed cells if placed where they are needed

Why should cells in the amniotic fluid give us information about genetic (and chromosomal) abnormalities of the fetus (and not the mother)?

the amnion (and of course the fetus) are of zygotic (as opposed to maternal) origin, so the fluid is surrounded only by cells from the fertilized egg

Under the influence of Mullerian inhibition factor (MIF) and (what else?) male development is initiated instead of the female default pathway.


How do the mitochondria in the sperm cell contribute to the DNA in the zygote?

They do not

Two meiotic divisions in the female result in only one "egg." What did the other nuclei produced by meiosis become?

Polar bodies

In cloning Dolly, an egg was obtained, its nucleus was removed, a somatic cell nucleus was put in, and cell divisions create an embryo (a hollow ball of cells) in vitro. What did they have to do after that so that a sheep was born?

Implant into a surrogate mother

Why would the intrauterine device (IUD) be considered to be particularly controversial?

Well, even blocking fertilization might be controversial, but blocking implantation is a really early abortion

Why does in vitro fertilization come up in discussions of the benefits and controversities of stem cell research?

One possible source of embryonic stem cells would be "left overs" once a couple has decided they have had enough children

How is it that a doctor can check for an enlarged prostate?

the latest in digital technology (there is no polite way to describe it but it involves a finger in a rubber glove)

Under what circumstances would a corpus albicans be formed?

without implantation, the corpus luteum regresses to the corpus albicans

In cloning Dolly, what did they need to do after they had a blastocyst?

implant it into a surrogate mother

Despite controversy, why would "left-overs" of in vitro fertilization have been perceived as particularly useful for theraputic purposes?

embryonic stem cells are pluripotent

Starting with a secondary spermatocyte (2n), two meiotic divisions gives 4 haploid (n) spermatids. Answer either (1) What happens to make those into spermatozoa? Or (2) What nearby supportive cell can assist in that process?

cyroplasm sloughed (and flagella added), Sertoli cell

Why does it make sense that surgical removal of a cancerous prostate might lead to incontinence (poor bladder control)?

the urethra passes through the prostate

Other than the seminiferous tubules and the prostate, name a gland that contributes to semen.

bulbourethral (Coper's), seminal vesicle

A sperm cell is about to meet a secondary oocyte (but they have not yet joined). Where, in the process of meiosis, is the egg?

before second meiotic division is completed

Where (anatomically) do cleavage divisions take place?

in the uterine (fallopian) tube

Why would using the "left-overs" of in vitro fertilization be particularly controversial for theraputic purposes?

the stem cells harvested are embryonic

***Blood and the Immune system

Thrombin acts on fibrinogen. Answer either (1) What is the activated product of fibrinogen? or (2) What is the function of that product?

fibrin, blood clotting

Monocytes. Answer either (1) After they migrate out of the blood stream and further develop, what are they called? or (2) What do they do in this new location and role?

macrophages, phagocytosis

Answer either (1) Why does flu still exist while smallpox has been nearly eradicated worldwide? or (2) Why does polio still exist while smallpox has been nearly eradicated worldwide?

flu mutates and has alternative hosts like birds and pigs, politics - some people think vaccination is an evil western plot

Antibodies interact with antigens. Answer either (1) What part of the antibody molecule binds to the antigen? or (2) What do we call the portion of an antigen molecule to which the antibody binds?

the variable part at the tip of the Y-shaped tetramer, epitope or antigenic determinant

In addition to destroying "microbes" through phagocytosis and lysosomal degradation, how can a macrophage communicate to a helper T cell about what antigens to "worry" about?

present antigen to helper T with MHC-2 and CD4

Why can I be reasonably certain that your MHC (major histocompatibility complex) is different from mine?

20 genes, 50 alleles each = lots of variability

MHC II is on macrophages and B cells. Why is it useful that MHC I is expressed in a wider variety of cells?

because a killer cell uses that to connect to any kind of cell that gets infected to kill it

Why was there a new "selection pressure" against hemopheliacs around 1980?

coltting factor, prepared from blood of multiple donors, might have HIV

A neutrophil arrives at the site of the injury. Answer either (1) What does it do when it gets there? or (2) What do they call the process of its attraction to move to tht site?

phagocytosis, chemotaxis

Why would blood cells be expected to agglutinate for a type B transfusion into a type A recipient?

the Y shaped antibody molecule can hold two red blood cells together.

There are some interesting differences in ABO blood groups vs. Rh factor antibodies. Answer either (1) Why would there be a bad reaction to the first type A transfusion into a B recipient? or (2) Why would an Rh- mother only have to worry (a lot!) about her further pregnancies after she has born an Rh+ baby?

there is already antibody, the IgG crosses the placent

In 1796, Jenner exposed people to cowpox to give them immunity to smallpox. What did Lady Montague do 3/4 of a century earlier to make people immune to smallpox?

she exposed them to smallpox itself

A naive B cell is exposed to an antigen and develops into a clone of plasma cells that produce antibodies plus (what other important type of cell?).

memory cells

At and after birth, an infant has the mother's immunities. Describe one of the two ways this happens with reference to the specific antibody involved in the mechanism you are describing.

IgG through placenta then IgA from breast milk

It was argued that Rasputin may, in fact, have been able to help Czarevitch Alexis. How?
The hemopheliacs bleeding might might have been decreased by getting vasoconstriction by controlling his sympathetic output to arterioles
What type of cell do monocytes (mononuclear cells) become after they are outside the circulatory system?
What does type O blood have or lack that permits type O individuals to be universal donors?
Type O red blood cells lack antigens, so that blood can be transfued into any recipient regardless of whether that person has antibodies
A molecule on the surface of a B cell was shown in one diagram as Y-shaped; it was called a "B cell receptor" and it was shown as binding to an antigen on a pathogen (probably a bacterium). What was this molecule? Be as specific as you can.
How does class-2 MHC assist a macrophage "tell" a B cell what antigens to "worry" about?
MHC-2 and CD4 corepressor are involved in the communication from the antigen presenting macrophage to the T cell

Hageman factor, prothrombin, thrombin, fibrinogen
What is the general term for blood that is deficient in red blood cells, hemoglobin, or iron?
After a white blood cell phagocytoses a bacterium, what does the white blood cell do to dispose of the ingested bacterium?
Combine this endosome with lysosomes
Mast cells help to mediate the inflammatory triad because they release (what substance?).
Address ONE of the following differences between ABO blood groups and Rh factor: (1) Whether antibodies are made after first exposure vs. they are already present. (2) Whether the couple might have to worry about a mismatch when having children. Or (3) Whether the antibody crosses the placenta.
Already present only for ABO, Worry for Rh only, IgG crosses placenta for Rh, not IgM for ABO
A naive B cell is exposed to an antigen. Describe the constituents of the clone of cells that develops from this cell.
Plasma cells make antibody, memory cells preserve the information
"Class-2 MHC molecules are expressed on macrophages and B cells." By contrast, where are class1 MHC molecules expressed?
Lots of cells
How do helper T cells assist killer T cells in their mission to destroy lots of cells that have been infected by the identified pathogen?
Via interleukin 2, they signal killer cells to proliferate
Say something you learned about EITHER IgA or IgE.
IgA is transferred to infant via breast feeding, IgE is involved in allergies
What kind of cell becomes a macrophage?


Presence of what in type O people would lead to agglutination if there were a transfusion with any other type of blood?

anit-A and anti-B antibodies

Presence of what in type O people would lead to agglutination if there were a transfusion with any other type of blood?

anit-A and anti-B antibodies

Eosinophils are a type of polymorphonuclear granulocyte. What is eosin?

a histological stain

What kind of molecule is IgG? (Be more specific than "protein.")


In a neutrophil or macrophage, after phagocytosis of a bacterium, what cellular organelle full of enzymes fuses with the phagosome to destroy the bacterium?


A B lymphocyte develops into what protein-producing cell?


When it is needed, what important protein does a plasma cell export?


What cell is specifically depleted in AIDS?

Helper T

The first vaccination was for what disease?

small pox

What are the two types of lymphocytes?


For Rh, a second exposure is very serious. Why is a first exposure, like a transfusion of the wrong blood group, bad in ABO blood groups?

there are already antibodies

A bacterium is engulfed into a vacuole in a phagocytic white blood cell. What cellular organelle, a bag of acid hydrolases, fuses with this endosome to destroy the bacterium.


Like neutrophils, monocytes infiltrate the injury site, attracted by chemotaxis. What is the difference in timing?

monocytes are later

Considering how much fibrin is around when clotting is needed, how come fibrin does not make blood clot all the time?

unless cleaved by clotting cascade, fibrinogen is inactive

Macrophages are derived from what type of white blood cell?


Why are the prospects for worldwide elimination of flu by immunization more elusive than for smallpox or polio?

evolution of virus in alternative hosts like birds and pigs

Antibodies produced by plasma cells are ineffective against infected cells. What specific type of lymphocyte destroys such cells loaded with foreign bacteria or viruses?

killer (cytotoxic) T lymphocytes

Class 1 & 2 MHC (major histocompatibility complex) molecules are expressed on the surfaces of various cells. Why is it almost guaranteed that yours are different from mine?

many genes, many alleles of each

If type A red blood cells are transfused into a type B person, antibodies in the type B blood will cause the red blood cells to clump. What is this clumping called?


What is the chemical signal that the helper T cell uses to cause the appropriate type of killer T cells to proliferate?

interleukin 2

Which specific antibody crosses the placenta to give the baby the mother's immunities early in life?


In what way is IgG different from IgM with regard to the placenta and blood groups?

IgG for Rh cross, IgM for ABO not cross

"Monocytes have a late chemotaxis and form macrophages." Translate.

these white blood cells are attracted to the site of injury after polymorphonuclear granulocytes and further develop into big phagocytic cells

Which specific type of white blood cell is depleted in AIDS (acquired immunodeficiency syndrome)?

CD4-expressing (helper)

Why are lysosomes an important part of phagocytic leukocytes?

they merge with endosomes to digest them

What kind of immunity does RhoGAM confer in the treatment for Rh- mothers?


Why is there a major difference between small pox and flu (influenza) with respect to the prospects for total elimination of the disease from the worldwide human population?

flu evolves and has alternative animal hosts

What purpose does IgD on the surface of B cells serve?

it is the antigen receptor

An allergen binding to IgE on the surface of mast cells causes the release of what substance from its granules?


Class II MHC (major histocompatability complex) is expressed only on macrophages and B lymphocytes. What about class I?

all cells, involved in attack on infected cells

Why is AB the universal recipient?

no A or B antibodies

Neutrophils, eosinophils and basophils are all white blood cells. Name a different type of white blood cell.

monocytes, lymphocytes (B and T)

Why is there so much variability in the MHC (major histocompatability complex)?

20 genes, 50 alleles each

Why is it beneficial for the infant that IgG crosses the placenta and that IgA is in mother's milk?

passive immunity from mother

CD8 vs. CD4 coreceptors distinguish what types of cell?

Killer vs helper T cells

What is agglutination as it applies to antibodies and the blood groups?

antibody causes cells to clump

We don't worry so much about blood type (ABO) of the fetus vs the mother, but we do worry about Rh factor. Why the difference?

IgM does not cross placenta, IgG does

For what is IgE most relevant?


How can MHC be so variable?

20 genes 50 alleles each

If all goes as "intended," what happens to a bacteria-containing endosome in a white blood cell?

becomes secondary lysosome after merging with primary lysosome (etc.)

Which blood cells are the precursors of macrophages?


Some bacteria come in through a small skin injury. How do phagocytitc cells get from an intact capillary to the site of the injury?

chem,otaxis, slither between endothlial cells

What is the major product exported from the B lymphocyte?

antibody molecules

What type of cells are the memory cells that can jump-start the response to the next exposure to an antigen?

B lymphocytes

What kind of protein is the antigen receptor on the surface of a B lymphocyte?

antibody (IgD)

What is the difference between an epitope and an antigen?

epitope (antigenic determinant) is the small portion of the antigen to which the antibody binds

How can an infant be immune to some diseases between birth and weaning?

IgG across placenta, IgA in milk

How would a blood count help to determine if you had a systemic bacterial infection?

There are more neutrophils in bacterial infection

Explain what agglutination is using transfusion of type A blood into a type B recipient as your example.

Antibodies would cause red blood cells to clump together

How can your immune system (conceivably) develop antibodies to every possible epitope?

The genes themselves get spliced to make the many variable regions

Class 2 MHC on the surface of an antigen-presenting macrophage acts in conjunction with (what?) on the surface of a helper T cell to activate it.


Why did AIDS, in the first few years, create a new "selection pressure" against hemophiliacs?

before AIDS, the "environment" was one where clotting factor was available through medical technology; after AIDS (before the blood banks were better secured) this factor from multiple blood donors had a grim chance of being infected

What does a phagocytic cell do to destroy a bacterium after it has "swalled" it?

presumably the endosome with the bacterium fuses with a primary lysosome, though some bacteria have evolved tricks to escape the endosome

"Monocytes have a late chemotaxis." Explain: either (1) later than what? Or (2) just what do are they doing that is called chemotaxis?

1-neutrophils, 2-slither out between endothelial cells

In what way do different antibodies create different risks for the fetus, comparing the ABO blood groups vs. Rh factor.

IgM not cross placenta but IgG does so 2nd Rh+ fetus is a problem for an Rh- mother unless she has antibodies after the first is born

"Clone" is a term applied in the discussion of the development of plasma and memory cells from B lymphocytes. What is that term meant to imply?

tha after a B cell is subjected to a particular epitope, a bunch of plasma and memory cells responsive to that epitope will form

To what fraction or portion of an antigen does an antibody bind?

epitope, 5 to 15 amino acids (also groups attached to them) near eachother

Address an infant's immunity answering either (1) what kind of antibody gave the newborn some of the mother's immunities at the moment of birth, OR (2) what kind of antibody from the mother can prolong the infant's immunity (that the mother had developed) for some time after that?

(1) IgG, (2) IgA

Address allergies with either (1) what kind of antibody is released from a plasma cell, (2) to activate what kind of receptor on the surface of a mast cell, OR (3) to release what substance from a mast cell.

(1) IgE (2) IgE receptor (3) histamine

CD8 coreceptor on a killer T cell acts in conjunction with (what?) on the surface of an infected cell to destroy that cell.

Class 1 MHC (also viral antigen)

What is the role of lysosomes in a polymorphonuclear leukocyte (granulocyte)?

they merge with ingested bacteria to "digest" them

What is agglutination, and why would you expect that reaction for a transfusion mismatched for ABO blood type?

clumping of red blood cells, happens because Y-shaped antibody molecule can stick several cells or clumps of cells together

At the moment of birth, an infant has some of the immunities of his or her mother. How?

IgG crosses the placenta

A killer T cell is activated by an antigen-presenting macrophage to kill cells infected with a microbe. It would sure be nice if a whole lot of killer T cells knew to kill cells with the antigens of that microbe. How does the immune system signal that proliferation?

interleukin-2 from a helper T cell

Why were hemopheliacs at particular risk for AIDS in the early days of the epidemic?

clotting factor needed to be produced from multiple blood donations before they knew to police the blood banks

In sexual dimorphism, why is the early development in the female considered to be the default pathway?

without TDF, indifferent gonads become ovaries, without MIF, Mullerian duct becomes uterus and tubes, without testosterone, embryonic structures become vagina, labia, clitoris

Suppose you get sick. What would they be looking for if they ordered a blood count?

white blood cell count increased in (bacterial) infection

For inflammation, answer either (1) What are the three components of the triad? Or (2) What chemical mediator from mast cells contributes to inflammation?

warmth, redness, swelling, histamine

What white blood cell was conspicuously reduced in AIDS?

helper (CD4 coreceptor expressing)

If an Rh- mother has an Rh+ child there is definitely a concern in later pregnancies. Not so if the child's ABO blood type does not match the mother's. Why the difference?

IgG crosses placenta, IgM does not

Smallpox and polio could be eradicated worldwide. Why not influenza (flu)?

flu mutates (changes) and has alternate hosts, especially birds and pigs

How does a B cell "learn" that it needs to initiate its response (making targeted plasma and memory cells) in response to a specific newly-"seen" antigen (that is out in the blood plasma)?

it binds that antigen with an antigen receptor that is an IgD

You get infected with the novel Stark-virus whose astounding property is that it has only one surface protein, and yet you develop many different clones of memory cells to protect you next time you are exposed. How could they be different when there is only one protein?

they would be against specific epitopes (antigenic determinants

A "microbe" is phagocytosed by a macrophage. How is it that a B cell can "learn" to make antibodies to the antigens on that microbe?

macrophage presents antigen and helper T cell presents it to the B cell

In cooperation with the CD8 expressing T cell, why is it important that MHC class 1 be expressed on cells in tissues that might be infected (in contrast with MHC class 2 that is only on macrophages [and B cells])?

MHC1 is part of the communication allowing this killer T cell to recognize and kill the infected cell

Why is there so much diversity in MHC?

20 genes 50 alleles each

***Touch and Motor

Why would it be useful to have rapidly adapting touch receptors, that rapid adaptation resulting in vibration reception at 250-300 Hz?

for active feeling touch of a textured surface

Your fingertips, tongue, and lips are very sensitive for fine touch. For instance a small thing stuck between your teeth feels bigger to your tongue than it looks when you floss it out. How is this difference (your legs, back and arms are not as sensitive) represented on the postcentral gyrus?

bigger areas for lips, fingertips and tongue

For motor function, describe the function of either (1) tie internal capsule, or (2) the nigrostriatal tract.

internal capsule has axons from precentral gyrus in corticospinal tract, nigrostriatal tract sends dopamine from substantia nigra to striatum

A cell body in the precentral gyrus sends an axon through a decussation in the medulla oblongata. Where does that axon make its synapse?

onto the spinal motor neuron in the ventral horn of the spinal cord gray matter

"An enzyme at the site of injury converts a precursor into bradykinin." What does this tell us about the somatosensory system?

nociceptors are actually chemoreceptors

A free nerve ending or an encapsulated touch receptor like a Pacinian corpuscle that mediates fine touch has an axon that comes into the central nervous system. Where does this cell have its synaptic termination?

way up in the medulla

How did they learn which parts of the body project to which parts of the postcentral gyrus?

gently stimulate the gyrus in a patient under local anesthesia ahd ask where (s)he feels a tingle

"If half of your spinal cord were lesioned, say as a result of an accident, you would have an ipsilateral loss of sensation mediated by the lemniscal system below the site of the injury." What is the situation (side of the body relative to which half is cut) for pain and temperature sensation below the site of the injury?


The corticospinal tract would be involved in arm and leg movements. In what way is this situation different for the face?

cranial nerves

In terms of the extrapyramidal motor system of the brain, answer either (1) where does dopamine come from? or (2) Where dies dopamane go to?

substantia nigra, striatum

"The thalamus is a motor relay." How can that be true when, in fact, the tract from the precentral gyrus to the spinal motor neuron does not have a synapse in the thalamus?

basal ganglia and cerebellum feed back to postcentral gyrus through thalamus

What would happen to the coding sequence of the mutant allele for Huntington's chorea from one generation to the next?

there would be more CAG's coding for more glutmines

A neurosurgeon applies a gentle electrical stimulus to the postcentral gyrus of an awake patient under local anesthesia. What does the subject say (or do)?
(s)he feels something on a certain area of the body
A somatosensory cell has a synapse in the dorsal (and lateral) part of the spinal cord. Where does the postsynaptic cell make its synapse in the brain?
Thalamus (spino-thalamic division of the somatosensory input)
The basal nuclei collect information from all over the brain and send it to (where?) to achieve better coordination of motor movements.
Motor cortex (via thalamus)

In the 1800s, a famous French physician studied stroke patients. What conclusions did he make upon examining their brains in autopsy that led to the naming of a brain area after him?
Broca found a small area on only one side of the brain that mediated the motor aspect of speech
Axons for one sensory system are in the dorsal columns. Answer either (1) Where are these dorsal columns? Or (2) What is being perceived by this sensory system?
Dorsal white matter of spinal cord, fine touch
Cells with sensory information make their synapses in the postcentral gyrus. Where are the cell bodies of these cells?
Cells in the precentral gyrus innervate muscles in the face via cranial nerves, while the tracts are localized (where?) to reach the motor neurons for the part of the body below the neck.
Anterior and lateral parts of the white matter of the spinal cord
"Huntingtons was found to be a triplet repeat disease." What does this mean?
One DNA triplet (CAG) coding for glutamine expands to too many copies
Basal nuclei (caudate, putamen, and globus pallidus), part of the extrapyramidal motor system, output through the thalamus to where?

the precentral gyrus

Faciculus cuneatus and fasciculus gracilis are part of what system?

lemniscal (for fine touch)

The gene (or gene product) of the gene that is abnormal in Huntington's chorea has a variable number of what?

CAG (glutamine)

Where is the decussation (cross over) of the lemniscal system for localized touch?

in medulla

A cell in the precentral gyrus whose axon is part of the corticospinal tract makes its first synapse on what cell?

spinal motor neuron

What is the function of the postcentral gyrus?

primary somatosensory projection

What is mediated by the spinothalamic (anterolateral) system that decussates at the level it enters the dorsal root?

pain and temperature

What are cells in the dorsal root ganglion used for?

somatosensory input to spinal cord

What property do the layers of encapsulation of a Pacinian corpuscle confer?

rapid adaptation

Between the tract called the medial lemniscus and the postcentral gyrus, there is a synapse in what famous "relay station?"


"The left half of the brain is for the right side of the body and vice-versa." Is this conventional wisdom true for pain and temperature as well as for fine touch?

yes, both, though crossings are at different levels

What is the function of the precentral gyrus?

voluntary motor initiation, motor cortex

Why is the anterolateral system so named (where is it?) and what is it used for?

location between anteriot (ventral) and lateral in spinal cord white matter, pain and temperature

Why is Huntington's disease sometimes called "chorea?"

chorea refers to jerky movements

Relate the expressions "triplet repeat" and "polyglutamine."

extra CAG's (nucleotide sequence) code for a string of glutamines (amino acid)

Where does a cell in the precentral gyrus make its first synapse?

Spinal motor neuron

In terms of localization of function of the cerebral cortex, what is the function of the postcentral gyrus?

somatosensory projection

How would the protein product of the Huntington's disease gene compare for someone without vs. with the disease?

more glutamines (amino acids) in a row with because of CAG triplet repeat

The output of the motor cortex (precentral gyrus, pyramidal system) goes all the way to the spinal motor neuron. By contrast, where do basal nuclei (extrapyramidal system) feed to?

thalamus, motor cortex

"That area of the skin, if deformed, that affects the response of one specific Pacinian corpuscle." What is this called?

receptive field

Serotonin is a mediator for nociceptors. Name another.

prostaglandins, leukotrienes, histamine, substance P, bradykinin

The spinothalamic system for pain and temperature is also called the anterolateral system. Why (does it have this other name)?

tracts are in ventral (anterior) and lateral parts of white matter in spinal cord

Between the pain receptor and the lateral spinothalamic tract, where is the first synapse?

in dorsal horn of spinal cord gray matter

Face and hand occupy about half the map of the motor cortex (precentral gyrus). How was this map determined?

stimulate brain of awake surgery patient and see where movement is

Earlier this semester, you learned that the substantia nigra does not make enough dopamine in Parkinson's disease. How does the substantia nigra feed into the motor system?

connects to striatum in extrapyramidal motor system

Voluntary motor movements for the face go out through cranial nerves. By contrast, what tract carries motor output from the motor cortex (precentral gyrus) to the lower part of the body?

corticospinal, pyramidal

Where is the cell body for the somatosensory receptor cell?

right outside the dorsal root of the spinal cord, dorsal root ganglion

What is the function of the postcentral gyrus?

somatosensory projection

Why would it be useful to have a touch receptor that is sensitive for vibration?

for active feeling

Where is the first synapse in the lemniscal input?

in the medulla (fasciculi gracilis and cuneatus)

What does it signify that the hand is as large as the arm on the motor cortex?

magnification where motor movements are more dextrous

In comparison with the extrapyramidal system, what is corticospinal spinal tract called?

pyramidal system

Where does the globus pallidus feed to?

to thalamus to motor cortex

The dopamine system is called "nigrostrital." Give the real names of the areas for which it got this name.

substantia nigra, striatum

"Nociceptors are chemoreceptors." Explain.

chemicals at the site of injury like bradykinin stimulate them

Where is the first synapse in the anterolateral input?

right in the dorsal horn

Why would half the children of a Huntington's victim be expected to get the disease?

autosomal dominant

Huntington's disease is called a "triplet repeat disease." Triplets of what?


Why does a textbook have a lateral view of the cerebral cortex which has different locations colored differently?

to emphasize localization of function, for instance sensory areas for different modalities

"A rapidly adapting pressure receptor is useful for active touch." Explain.

As you feel a textured surface, that receptor is vibrated

For the anterolateral system, a cell in the dorsal horn of the gray matter of the spinal cord makes its synapse (where in the brain?).


(Refer to the previous question.) "This anterolateral system ultimately projects to the same part of the cerebral cortex as another system. Answer either (1) What is this part of the cortex called? Or (2) What is this other system? (name, location in spinal cord, OR function will suffice).

(1) motor cortex = precentral gyrus (2) lemniscal carried in dorsal columns mediating fine touch

"The corticospinal tract is for voluntary motor output." What about the face?

Cranial nerve 5 trigeminal

"Huntington's disease shows 'anticipation,' getting worse from generation to generation." What changes (molecularly)?

Nucleotide triplet CAG (that codes for glutamine

WHY (note, I am just asking why) would a half spinal cord lesion affect senses mediated by spinothalamic vs lemniscal systems below the injury differently?

Where they cross over is different, spinothalamic below the lesion, lemniscal above

How was the map of the postcentral gyrus obtained?

Gently electrically stimulate and ask the person where (s)he feels it

"The thalamus is a relay (more than a relay!) for sensory and motor systems." And yet the corticospinal tract went right past the thalamus without making a synapse. In what system, then does the thalamus have motor synapses?

Extrapyramidal - basal ganglia feed back to motor cortex via thalamus

What is the use of having a receptor like the Pacinian corpuscle that is responding to vibration at 250 to 300 Hz?

in active touch (feeling), a textured surface will stimulate a given receptor with vibration

Explain the mechanism of nociceptor function in terms of bradykinin.

it is a chemoreceptor responsive to signals indicating tissue damage like bradykinin

A receptor mediating fine touch discrimination comes into the spinal cord at the dorsal root ganglion. Where does it make its first synapse?

in the medulla

For the lemniscal system, answer either (1) Why is it called the lemniscal system? Or (2) What specific portion of somatosensory function does it mediate?

there is a tract in the brain called the medial lemniscus, fine touch discrimination

In brain surgery under local anesthesia, how would the subject respond to gentle electrical stimulation to any given spot on the postcentral gyrus?

(s)he would indicate that (s)he felt something (relating to the map)

"The decussation of the pyramidal tract" Answer either (1) At what level is it? Or (2) What is it called (as it descends after it decussates, please do not repeat "pyramidal tract")?

medulla where pyramids are seen, lateral corticospinal tract

"The motor impairment from a half spinal cord injury would be ipsilateral." Why?

after the decussation, tract is on the same side of the body as the muscles it innervates

Motor output to the face is not in tracts in the spinal cord. What nerves or tracts send voluntary motor output to the face?

facial nerve (and some other cranial nerves)

Name a structure in the extrapyramidal system that is functionally between the substantia nigra and the thalamus.

caudate, putamen, globus pallidus, striatum, lentiform nucleus

In Huntington's chorea, what would change (molecularly) if the disorder were worse one generation than in the previous generation?

the triplet (CAG) that codes for glutamine

A receptor mediating pain or burning sensation comes into the spinal cord at (what?) ganglion?

dorsal root ganglion

What is it that is anterior and lateral that gave the anterolateral system its name?

tracts in the white matter of the spinal cord

For the basal ganglia (nuclei) explain the naming of either (1) the lentiform nucleus or (2) the striatum.

lens shaped in horizontal secton, looks striated from branches of internal capsule

"In a sense, Huntington's is the opposite of Parkinson's." How so?

hyperkinesia vs hypokinesia


Name (or give the number for) one of nerves that connect the taste receptors to the brain.

vagus 10, glossopharyngial 9, mostly facial 7

A gustatory receptor sensitive to quinine has a G protein-coupled receptor; the cascade results in calcium ions being released from an endoplasmic reticulum. Why would an increase in cytoplasmic calcium ions be useful in gustatory receptors?

for release of synaptic transmitter vesicles

Monosodium glutamate affects which taste receptor primary?


The diagram of axons from olfactory receptors does not show connection to the closest glomerulus. What characteristic of the olfactory receptor determines which glomerulus it connects to?

ones that respond to the same primary pool to the same glomerulus

Approximately how many G protein coupled receptors are there for human olfaction?

lots, 500-1000

Gustatory receptors connect to cranial nerves that project to the brain. Name one of the three places in this projection pathway.

medulla, thalamus, postcentral gyrus

What is the cause of the difference among the students in the physiology class as to whether they could taste PTC?

genetic, non-tasters are homozygous recessive

When a G protein coupled cascade in an olfactory receptor alters the cAMP level, what does this cAMP do?

gates a channel

Say something about what "hair" means with respect to hair cells in the vestibular or auditory systems.

real cilium=kinociliun and cilia-like stereocilia

Some taste cells depolarize in response to the appropriate chemical stimulation. What must happen, downstream of depolarization, for vesicles of neurotransmitter to be released?
Calcium ions must come in through calcium channels
Contrast how cAMP gates a cation channel in an olfactory receptor cell with the way acetylcholine gates the nicotinic receptor.
cAMP from inside the cell, Ach from outside, both channels are ligand gated

The receptor molecule for gustation is either (what?) or (what?).
a channel or a G protein coupled receptor
The chemoreceptive part of the olfactory cell is in the nasal cavity. Where is the synapse?
In the olfactory bulb (first cranial nerve) of the brain
In the vestibular system there are 3 fluid-filled (what) plus 2 organs with otoliths, the (what?) and the (what?). [Answer one of the above.]
semicircular canals, utricle & saccule

What type of molecule must come in many varieties to mediate the richness of olfaction you enjoy?

G protein linked receptor

Where is the first synapse in the olfactory system?

olfactory bulb

What is detected when endolymph bends the cupula?

head rotation

What does the term "umami" refer to?

a taste, glutamate

Which sensory system projects to the limbic system, including the amygdala?


After a bitter tastant causes Ca2+ to increase in the cell, what does that Ca2+ do?

cause transmitter release

Out of the 5 special senses, which one does not have a localized area of the cerebral cortex as its final projection?


About how many different G protein coupled receptors are involved in human olfaction?


In addition to the vestibular sense, which utilizes hair cells where "hair" refers to stereocilia?


All taste cell types, by one mechanism or another, have an influx of Ca2+. What process does this increased cytoplasmic calcium mediate?

synaptic vesicle release

A portion of the brain hypothesized to be involved in olfaction, emotion, and memory.

limbic system (or any part of it)

What is PTC (phenylthiocarbamide) and what did it reveal about sensory transduction?

a substance that tastes bitter and helped in the isolation of the G protein-coupled receptor

How is the richness of olfactory experience coded in the genes for olfactory receptor molecules?

a different gene for each G protein-coupled receptor, very variable

Upon stimulation, for each taste primary, cytoplasmic Ca2+ increases. What is it used for?

for release of transmitter vesicles

The ciliary receptor cells in the nasal epithelium have axons that terminate (where)?

olfactory bulb (first cranial "nerve")

What brain center involved in motivational aspects of hunger does the olfactory bulb project to?


There are three nerves that carry taste information to the brain. These three nerves are among a famous set of about a dozen that are collectively referred to as (what)?

cranial nerves

In olfactory transduction, what does cAMP do to affect the electrical properties of the receptor cell membrane?

cAMP is the ligand that gates the cation channel from inside the cell

Where are the sense organs that monitor your head position to keep your eyes upright for slight tilting of the head?

near the cochlea (for hearing)

In what way does the tastant for umami relate to a central nervous system excitatory neurotransmitter?


About how many olfactory receptor molecules does a human have?


In addition to G protein-coupled receptors, what is the other type of taste receptor molecule?


In taste receptors, Ca2+, mediating transmitter release, comes from either outside the cell or (what subcellular structure?)?

endoplasmic reticulum

Where do olfactory neurons make their synapses?

olfactory bulb

What are the "hairs" of hair cells, and what happens when they are bent?

cilia (stereocilia), open or close channel, depolarize or hyperpolarize

In what way are calcium ions essential for the signaling of the taste receptor cells to the cranial nerves?

mediate exocytosis of vesicles

In some cases, taste receptor molecules are channels. Alternatively they are (what?).

G protein coupled receptors

Why do olfactory axons seem to zig-zag rather than just connect to the closest glomerulus? (That pertained to yellow and green receptors, as colorized in your figure, connecting to yellow and green glomeruli.)

presumably, each glomerulus receives only from receptors expressing the same receptor

In the G protein-coupled receptor cascade in the olfactory cell, how did the cAMP affect the cell's response?

ligand close K+ channel

Describe the receptor cells of the vestibular system with respect to their (1) structure, or (2) the type of stimulus that excites them.

(1) "hair" cells with stereocilia, mechanical

On the back of the tongue, taste buds are found on what larger structure (hint, nine of them, and the nerve projects by the IX cranial nerve, the glossopharyngeal).

Circumvallate papillae

65. In terms of the respective molecular biology of transduction, why is olfaction a much richer sense than taste in humans?

There are maybe a thousand receptors for different primaries

Where is the first synapse in the sense of taste?

in the taste receptor cell

In olfactory transduction, what does cAMP do?

ligand for channel

By looking in the genome at G protein coupled receptors, what was isolated when responders vs. nonresponders to PTC (phenylthiocarbamide) were compared?

bitter taste receptor

For the fifth taste primary (other than sweet, sour, salt and bitter), what chemical(s) stimulate it?

glutamate, amino acids

Where is the first synapse in the sense of smell?

olfactory bulb


Say something about what "hair" means with respect to hair cells in the vestibular or auditory systems.

real cilium=kinociliun and cilia-like stereocilia

"Helmholtz probably thought the basilar membrane was like a harp when he formulated his place theory." That is one way of looking at the finding. In what way did Bekesy's Nobel prize winning data disprove such a model?

localization was cruder than strings on a harp

One tuning fork sounded higher than the other in our classroom demonstration. How did we "calibrate" (in the classroom) how much they differ in Hz?

by how many beats there were

In what way is the very low number (0.0002 dynes per square centimeter) fundamental in human hearing?

the standard pressure (denominator) in the definition of dB

When the mechanoreceptive channel on an auditory receptor opens, potassium ions come into the cell through that channel. What makes that unusual direction possible?

the extracellular fluid is high in potassium ions

"Bekesy's Nobel prize winning research confirmed Helmholtz's place theory." That is one way of looking at the finding. In what way did Bekesy's work confirm Helmholtz's theory?

different frequencies preferentially vibrated different places on the basilar membrane (though crudely)

Say something about tonotopic organization of sound on the cerebral cortex.

on the auditory cortex on the temporal lobe, different frequencies are represented in different places

Some animals can hear ultrasound. How does ultrasound differ from the sounds humans can hear?
It is a higher frequency, higher than 20,000 Hz
The endolymph fluid in the cochlear duct (scala media which bathes the stereocilia) is unusual (for an extracellular fluid) in that it contains a high concentration of (what?)
Helmholtz envisioned that each different frequency stimulated a specific place along the basilar membrane, and that was the explanation why frequency discrimination was so good in the human. How did Bekesys data or explanation differ from Helmholtzs original place theory?
The localization was far from pinpoint, so neural processing (lateral inhibition) was invoked to explain why the crude place localization would still be sufficient
There are four or five synapses in the auditory pathway. Where are the terminals of the cells in the thalamus (that receive synaptic input from >further down,< the inferior colliculus)?
On the auditory part of the cerebral corgtex
Stereocilia in human audition are bent as the basilar "membrane" moves relative to what other "membrane?"
Name one of the two differences (between sound in one ear vs sound in the other ear) that contribute to auditory localization in the human.
Time of arrival (because of distance and the speed of sound) and intensity (because of the sound "shadow" of the head)
Helmholtz's place theory for frequency discrimination refers to place on what membrane?


Because the perilymph cannot be compressed, pressure applied at the oval window is released where?

round window

If the pressure is 0.002 dynes/cm2, 10 times the standard for audition (0.0002 dynes/cm2), how many dB is the sound?


The stapes drives vibrations to what structure?

oval window

If two audio oscillators set to about 1000, playing through loud speakers, give 5 beats per second, what would you perceive if you heard one then the other sequentially?

you would hear distinctly different pitches

In addition to the vestibular sense, which utilizes hair cells where "hair" refers to stereocilia?


For people, in addition to intensity of sound for one ear vs the other, what contributes to auditory localization?

time of arrival

What does "tonotopic" refer to with respect to organization of the cortical projection for hearing?

different frequencies project to different places in an organized way

A log unit is an order of magnitude, i.e. 10 x. How many dB per log unit?


Tip links between stereocilia contribute to channels responsible for what kind of stimulation?

mechanosensation, or hearing, possibly K+

If a certain sound is 20 dB louder than another sound, how many times as loud is it?

10 x (one log unit)

Why is it reasonable to propose that a sound might arrive at the two human ears at different times?

speed of sound is finite (slow) and head is big

Why was it useful to hold the tuning fork and loud speaker to one ear simultaneously before demonstrating frequency discrimination by holding them to one ear sequentially?

beats prove that two stimuli differ by only a few Hz

"Hairs" on hair cells bend when the basilar membrane moves with respect to what other membrane?


A young human can hear frequencies from about 20 Hz up to about (what)?


In what way is K+ particularly relevant to auditory transduction?

K+-rich extracellular endolymph in scala media (secreted by stria vascularis) makes it so that, when channels open, K+ comes into cells

Helmholtz proposed that different frequencies stimulated different places along the basilar membrane. In what way(s) was his place theory confirmed or contradicted?

true, but localization is crude, lateral inhibition corrects for this

The vestibular apparatus shares a nerve to the brain with what special sense?


"There is tonotopic localization in the auditory cortex." Explain.

different frequencies at different locations in an order

"The audibility curve extends from about 20 to 20,000 Hz." What would be the most obvious difference (from this statement) among the people in the room where your physiology course was taught.

your professor would have an age related loss at higher frequencies

Why is the round window useful, in fact necessary?

to release pressures applied to oval window since fluid cannot be compressed

What is compared that would allow you to tell which side of your head a sound is coming from?

inputs from the two ears

How is it that K+ moves in, rather than out, through channels in auditory hair cells?

an unusual extracellular fluid (endolymph) is high in K+

About how many Hz is the just noticeable difference at 1000 Hz?


Twenty times the log of one pressure divided by 0.0002 dynes/cm2 tells us what property of sound?


There is a cut-off of (what? - give number and units) between "sound" (that humans can hear) and ultrasound (such as dogs and bats can hear).

20,000 Hz

"Helmholtz was correct in general but wrong in the details" (about frequency discrimination). How so?

Bekesy demonstrated that different freqencies stimulated different places, but more crudely than Helmholtz imagined. (need latreral inhibition to process)

The sound may arrive at one ear 700 microseconds before the other ear. Answer either (1) How can this be? Or (2) Why is that useful?

(sound has a finite (slow) speed considering the size of the head

Movement of the organ of Corti relative to (what adjacent membrane?) causes the "cilia" of auditory hair cells to bend.


K+ comes in through the auditory cell channel. Now, wait a doggone minute. How did that happen?

b/c K+ is high, which is unusual, in the extracellular fluid (endolymph)

The vestibular system is composed of three (______) ane the (_____) and the (_____), Fill in at least one blank.

utricle, saccule and semicircular cannals

"Sound intensity is measured in log units." Be more specific than that.

dB is 20 log ratio of pressures

Why does Bekesy's description of vibrations in the basilar membrane fail to verify Helmholtz's place theory unless neural processing (lateral inhibition) is invoked?

the place localization is very crude

Name at least one synaptic location between the organ of Corti and the auditory cortex.

cochlear nucleus, medial geniculus, thalamus

Why is the ion flow unusual when the hair cell's potassium channel opens?

high extracellular K+ means it goes in


Blind spot, answer either (1) In terms of anatomy, why is this found on the temporal VISUAL field? or (2) Why is that area blind?

because the optic nerve exits the eye on the nasal RETINAL field, there can be no receptors where the optic nerve exits the eye

Why would you have tunnel vision in retinitis pigmentosa?

loss or rods in the mid-periphery

Glaucoma: answer either (1) What compartment does not drain properly in this disorder? or (2) What is the mechanism of loss of vision (blindness) [e.g. media lose their transparency, refractory error, etc].

aqueous humor (anterior chamber) ganglion cells (the ones that form the optic nerve) degenerate

"A laser is used to destroy patches of the retina." Answer either (1) Who might actually benefit from this procedure? or (2) Why would the ophthalmologist avoid blasting the fovea with the laser?

a diabetic, fovea is too essential for high acuity color vision at the point of fixation

What kind of people would have the focussed image in front of the retina instead of on the retina?

near-sighted people

If the ciliary muscle is contracted, what happens to... (answer one of these) (1) the suspensory ligaments, or (2) the shape of the lens, or (3) your eyesight?

they become slack, it gets rounder, for near vision

"Eye care professionals dilate the pupil with belladona alkaloids." Pretend this is all you know and then explain, on that basis, what output from the parasympathetic nervous system does to the pupil.

drug blocks parasympathetic neuro-effector junction, so parasympathetic must do opposite, constrict

"A single rod can 'see' one photon of light." How is it that such a cell physiology piece of knowledge was first established on the basis of ordinary people like you and me indicating whether or not they could see various light stimuli?

psychophysics, careful calibrations, careful measurements, showed only 6-14 quanta absorbed over a 500 rod area

A cis to trans isomerization of what chromophore, (name that chromophore), a component of a G protein coupled receptor, is the only thing light actually does in visual transduction?

11-cis retinal (retinene) the aldehyde of vitamin A

I suggested that a gene duplication on the X chromosome could be used to explain how the superfamily of G protein coupled receptors evolved. Which two proteins are made by the two duplicated X chromosomal genes I am referring to?

the genes for red- and green-absorbing rhodopsins

Rhodopsin signals to a G protein and the G protein signals to what enzyme? Answer for either the vertebrate or for the fruit fly. Hints: cGMP is involved in the vertebrate rod and the fly utilizes the phosphoinositide signal transduction cascade.

a phosphodiesterase that converts cGMP

Coated pits and multivesicular bodies are involved in recycling of photoreceptive membrane in fruit flies. By contrast, for vertebrate rods, an additional type of cell is needed in the phagolysosomal system. What is this cell called?

retinal pigmen epithelium

Why are you blind in your blind spot?
No receptor cells can be presen t where the optic nerve exits and the blood supply enters and exits
What happens to your vision when the ciliary muscle is contracted?
When ligaments become flaccid, the lens gets rounder, accommodating for near vision
"Night blindness," "ring scotoma," and "tunnel vision" are symptoms of what disorder?
Retinitis pigmentosa
Which portion of the nervous system connects to the iris to mediate the constriction of the pupil elicited by a light stimulus?
Parasympathetic, occulomotor nerve (#3), from ciliary ganglion
Why is there lutein in your vitamin pill?
This is one of the carotenoids in the macular pigments that protect foveal cones from blue light
Young and Helmholtz proposed a widely accepted theory of trichromatic color vision in humans. Answer either (1) what kind of cell, or (2) what kind of molecule has these three specific peak wavelengths of sensitivity?
Cone rhodopsin
Why is it more accurate to refer to women heterozygous for red or green blindness as "mosaics" instead of "carriers?"
since it is on the X, they have some cells with one X and the rest of their cells have the other X
In Prof. Stark's research seminar, the rhodopsin promoter or the heat shock promoter was used to drive expression of rhodopsin labeled with green fluorescent protein into the rhodopsin-containing organelle that mediates vision. On what kind of molecule is a promoter?
The promoter is the part of the gene upstream of the coding sequence (thus DNA)
Prof. Stark showed transmission electron micrographs from his own work and work from other researchers of big vesicles in the visual cell that he believed carried rhodopsin into the rhodopsin containing organelle that mediates vision. What cell structure would have produced these vesicles?
Rough endoplasmic reticulum via Golgi apparatus
State a major difference between retinitis pigmentosa and age related macular degeneration.
Rods (as young adult) ve cones (in elderly)
State one of the three fundamental functions of the retinal pigment epithelium.
Black "paint," retinoid metabolism, phagocytosis of distal tips of rods that are shed daily
The aldehyde of vitamin A (retinal, formerly called retinene) is hit by light. What happens to it?
It bends [isomerizes] (it relaxes from 11-cis to all trans)
Under what circumstances is there lots of cGMP to open the channels in the rod outer segment?
In the dark
In Prof. Stark's research seminar, a recent suggestion was that clathrin was associated in an "import" pathway (rough endoplasmic reticulum to Golgi apparatus to the organelle where rhodopsin mediates vision). More traditionally, for many decades, clathrin was seen (in what structure?) in the transmission electron microscope.
Coated pits, coated vesicles, endocytitic structures, clearance
In what context is vitamin A relevant to a G protein coupled receptor?
The aldehyde of vitamin A is the chromophore that attaches to the protein rhodopsin (which is a G protein coupled receptor)
What intracellular ligand, whose function is to open channels, is decreased when light stimulates a rod?


Energy equals Planck's constant times the frequency. Energy of what?

of one photon

For what population of people is macular degeneration most common?


What must be bound to the G-protein-coupled-receptor protein to make the fully-functional rhodopsin molecule that absorbs light?


What happens to a rod's neurotransmitter release when light hits the rod?


The ciliary muscle contracts, in accomodation, to let you do what?

see up close

How does an eye care professional test for glaucoma?

poke the eye for a pressure check

In the dark, a current of Na+ ions flows from the sodium pump in the inner segment through what in the outer segment?


When an axon from a ganglion cell goes toward the brain in the optic nerve, where does it first synapse?


What layer at the back of the eye is black?

retinal pigment epithelium, also choroid

Some men taking Viagra (sildenafil) report impaired color vision. Why might this be?

Viagra and phototransduction both involve cGMP

Where are the genes of the long- and middle-wavelength cone rhodopsins located?

X chromosome

Our gaze seems more relaxed for far vision even though suspensory ligaments are relaxed for the lens to accomodate for near work. What does contract to change the lens shape to see up close?

ciliary muscle

A current of Na+ in the dark along the rod is from the Na+/K+ pump in the inner segment and what in the outer segment?

Na+ channel (or transduction machinery)

What specific cellular defect explains the tunnel vision (ring scotoma) of retinitis pigmentosa?

rods degenerate

What is the only direct effect of light in initiating phototransduction?

cis -> trans isomerization of retinal

What kind of lens corrects for myopia (near-sightedness)?


Which two rhodopsins used for human color vision are coded by adjacent genes on the X chromosome?

middle and long wavelength (green and red [yellow])

Ganglion cells are killed from high eye pressure. What is this disorder called?


What layer of black cells supports rod outer segments by phagocytosis and conversions of vitamin A?

retinal pigment epithelium

Epinephrine binds one G protein-coupled receptor (GPCR). What other GPCR, used for vision, is a pigment that contains a form of vitamin A?


As it applies to diabetic retinopathy, what is angiogenesis?

formation of new, fragile, blood vessels

Laser photocoagulation decreases angiogenesis. Here we are treating to prevent further blindness from what disorder?


Which side of the retina projects to the ipsilateral lateral geniculate body at the optic chiasm?


Macular degeneration (MD) aflicts a certain population as reflected by the "A" in the name (AMD). What population?

elderly (A=age-related)

Under what conditions are cGMP levels in the rod lowered?

when stimulated by light

Why is it inaccurate to consider a chromosomally normal woman to be be a carrier for a recessive X-linked color blindness if the other chromosome is normal (wild-type, dominant)?

mosaic of cells with one vs the other X functioning (Mary Lyon X inactivation hypothesis)

Why does each eye have a blind spot?

there can be no receptors where the optic nerve exits

Why is cataract usually a less severe form of blindness than retinitis pigmentosa?

there is straightforward surgery for cataract, whereas rods die and cannot be recovered for rp

Scientific information has led to the decades-old conventional wisdom that vitamin A is good for vision. Other than being the pigmented portion of rhodopsin, where else do carotenoids come in to play, explaining why lutein is a dietary supplement or a component in a multi-vitamin pill?

macular pigments protect fovea from blue light

Presbyopia is a defect in what process that affects most people over 40 years old.


Why is the cornea actually a stronger lens in the eye than the lens?

because of the big change in index of refraction from the air-cornea interface

Why is the rod depolarized in the dark (but not in the light)?

because cGMP opens sodium channels

The genes for the yellow- and green-light absorbing rhodopsins are near each other on which chromosome?


The tip of the rod outer segment is sloughed off on a daily basis and "recycled." Where does this cellular fragment go?

into retinal pigment epithelium

What does activation of the parasympathetic portion of the occulomotor nerve do to the pupil?


If your eye pressure is high, answer ONE of the following: (1) name of disorder, (2) what is not draining appropriately, or (3) loss of what cells mediates vision loss?

glaucoma, aqueous humor, ganglion cells

How can rhodopsin be mutant yet the patient still can see until retinitis pigmentosa first presents in the teens or 20's?

in autosomal dominant, a normal recessive gene still expresses rhodopsin

Suppose you could stimulate a nerve to achieve the same effect as applying belladonna alkaloids to the eye. What type of nerve would you stimulate?


A whole lot of rods converge onto each ganglion cell. What does this wiring achieve?


What is lost in age related macular degeneration (AMD)? (Your answer can be cellular or functional.)

cones, fovea; vision

If you stare straight at a mark (X), while a stimulus is presented to both eyes to the right of the X, describe how the stimulus projects to the thalamus (lateral beniculate nucleus).

temporal retina of left eye - ipsilateral projection; and nasal retina of right (contralateral) to left

In the molecular mechanism from light absorption to hyperpolarization of the rod, exactly what does 11-cis retinal do?

absorb light, convert to trans

Why would you see much better under water with vs without goggles?

keep the normal air-cornea interface (with the normal indices of refraction)

"The blind spot is about 15o off fovea in your nasal retinal field (temporal visual field)." Translate.

location off axis is measured in angle, since the optic nerve exits 15o on the side toward the nose, the inversion of the image would make it seem 15o off to the side

"Visual experience can influence the progression of myopia." On what basis can that statement be made with scientific authority?

research where the vision was distorted with goggles and the eye changed

"If the ciliary muscle is relaxed, the ligaments are tight and" Finish this thought with respect to the shape of the lens and what that does for vision.

lens flattens for distance vision

In the course a lifetime, a retinal pigment epithelial cell's ability to carry out it's function might deteriorate. Why?

it fills with the indigestibloe residue of the phagolysosomal system

If you were convinced that blue light damages foveal cones, how might you alter your diet starting now, while you are young, to delay age related macular degeneration (AMD)?

eat veggies or vitamin pills with lutein or zeaxanthin

With what sort of methodology were scientists as early as 1942 able to come to the conclusion that a rod can respond to one photon?

psychophysics, human subjects report if they can see calibrated lights

"A derivative of vitamin A is the chromophore of rhodopsin." Translate.

vitamin A aldehyde is the light absorbing portion attached to the protein

Why would the evolution of red-green color vision on the X chromosome relate to the richness of olfactory sensation?

it is a simple example of the evolution of G protein-coupled receptors

"Color normal is dominant, color blind is recessive, hence women can be heterozygous carriers for green blindness." Why is this an oversimplification?

they would be mosaics of cells with one or the other X functioning

Why is there an extracellular current from the rod outer segment to its inner segment in the dark?

The channel letting Na+ in is in the OS, the sodium pump is in the IS

In terms of the channel gating, why does a rod hyperpolarize in response to light?

the ligand (cGMP) that holds the Na+ channel open is broken down

You stare at an X with your right eye. Answer either (1) Where would the blind spot be? (state this using the sort of terminology that might be used in optometry) Or (2) How would you determine where it is while you are staring at the X?

a certain angle (about 15 degrees) off axis (away from the fovea) in the temporal visual field (nasal retinal field)

A muscle that mediates accommodation contracts. Answer either (1) What happens for your vision? Or (2) What happens to the shape of the lens?

(1) better for near vision (2) becomes rounder

"The loss of vision is referred to as a 'ring scotoma.'" Answer (1) What disorder? Or (2) Why is it a ring?

1-retinitis pigmentosa, rods (in mid-periphery) are lost

Which portions of the nervous system mediate constriction and dilation of the pupil?

parasympathetic (constriction) and sympathetic (dilation)

One photon absorbed by rhodopsin elicits an electrophysiological response in a rod. That plus what retinal wiring consideration makes scotopic vision tremendously sensitive?

convergence of multiple rods to one ganglion cell

Why does the retinal pigment epithelial cell have so much to phagocytose?

tips of outer segments are shed daily

How (between New World monkeys and Old World monkeys) did there get to be (at least) two color vision genes on the X chromosome?

unequal crossing over duplicated the gene

What is the only thing that light does directly to excite rhodopsin?

cause 11-cis to all trans isomerization of retinal

A light is switched on. What happens to the transmitter release from the rod?


The eye pressure is high. Answer either (1) What isn't draining properly? (2) Death of what cell type would mediate vision loss? Or (3) What is this condition called?

Aqueous humor, ganglion cell, glaucoma

Why would a person with my interests need to use Planck's constant?

Since it gives energy of a photon, it can assist in calculations of light intensity

When an ophthalmologist looks at your retina, what is the second most conspicuous landmark after the optic disc?

Macula (fovea)

What does the Mary Lyon X inactivation hypothesis have to say about heterozygous carriers of red or green colorblindness (both of which are on the X)?

It should not be a matter of dominant vs recessive, but her retina must be a mosaic

What is it that allows the sodium channel in the rod outer segment close?

Removal of cGMP by phosphodiesterase

In the visual projection, where is the first place where inputs from both eyes can connect to the same cell?

Not until the cortex

What is lost making people with age related macular degeneration (AMD) blind?

Cone (foveal) vision

How is vision changed when suspensory ligaments are relaxed?

lens rounder for near vision

What would output from the occulomotor nerve (cranial nerve #3), connecting through the ciliary ganglion, do to vision in bright light?

parasympathetic constrict pupil to decrease that bright light to retina

Who was short-changed by the bottleneck proposed for the evolution of color vision?

early mammals

Why might you expect that medications like Viagra for erectile dysfunction might affect vision?

It inhibits cGMP phosphodiesterase

Fish, birds and mice can see ultraviolet light but you cannot. What is the difference between their eyes and yours in this regard?

obviously, their lenses must transmit UV, also their retinas have UV receptors

What happens to the vision of a fruit fly in a mutant that has degeneration of the predominate receptor type, R1-6?

R1-6's contribution to response is abolished, leaving R7 (with its UV sensitivity) and R8 contributing to physiological and behavioral response

How was it first shown, a few decades ago, that there were environmental (not just genetic) influences in progressive myopia?

vision changed in chicks pecking for seeds if they were fit with goggles

What part of the eye is at fault when the subject experiences floaters?


"Ring scotoma." Answer either (1) Why a ring? Or (2) What is the name of this disorder?

since rods are off fovea, ring of rod blindness is around fovea

A pigment that looks yellow and absorbs blue light is situated in the light path on the way to the foveal cones. Answer either (1) What is it made of? Or (2) How might it be useful in terms of visual health?

carotenoids (zeaxanthin and lutein), might prevent or delay age-related macular degeneration

Either remember or figure out from what I remind you. Planck's constant (h) is 6.63 x 10&shyp;34 (what units?) E is energy, frequency (n)= speed of light divided by wavelength of light. E=hn.


Phagocytosis by the retinal pigment epithelium (RPE). Answer either (1) What is phagocytosed? Or (2) Describe, in some way, the burden this imposes on the RPE cell.

distal tips of rods, postmitotic cells last a lifetime and such high traffic leads to accumulation of age pigment

What is the next molecule in the cascade directly after the G protein (transducin) is activated?

cGMP phosphodiesterase

I can see 350 nm light but you cannot. Why can't you see UV (ultraviolet) light?

your lens blocks it

Give the approximate wavelength for the peak sensitivity of human rods?

500 nm

When it was first introduced by Harris, Stark and Walker in 1976, what was the sev (sevenless) mutant used for?

to show that R7 was a UV receptor, to show the contribution of R7 to the (spectral) responsivity of the eye

What happens to the vision of a vitamin A deprived mouse after it has had vitamin A replacement therapy?

since it was very low, it comes up, it comes up in the UV especially