1. Why is sweating so useful in human temperature regulation?

it requires a lot of heat to convert liquid water to water vapor

2. Why would you expect much less corticotrophin releasing factor than adrenocorticotrophic hormone?

crf is delivered through the portal system, acth through the systemic circulation

3. Why would a person with untreated diabetes lose some of the calories (s)he has consumed (rather than use them)?

glucose is lost through the urine

4. If you inject current in one direction, you depolarize the membrane. If you inject current in the other direction, what is the term used to describe what you do to the membrane?


5. What is the source of the heat that is available to keep our body temperature at the set point?

heat is generated by catabolic metabolism since ATP production is far less than 100% effective

6. What is there too much of in a person with goiter?

tsh (thyroid stimulating hormone)

7. A monolayer of phospholipid floating on a water bath has a certain surface area. What other information was needed for Gorter and Grendel to conclude that there is enough phospholipid in a red blood cell ghost's membrane to make two layers?

how many red blood cells went into the extract plus the size of the cell

8. A membrane is unable to pass water or ions. Then how come rhodopsin can sit in the membrane?

there are hydrophobic amino acids in the 7 transmembrane alpha helices

9. "You can see the hydrophilic layers of the membrane and they are dark, while the hydrophobic layer is light." This is a very careless way of stating the appearance of a membrane in the electron microscope. Make part of this statement more scientifically accurate.

"dark" is electron dense because of staining with heavy metals, and "light" is the opposite

10. Phospholipase C creates signaling molecules from PIP2. Answer EITHER (1) Which signaling molecule is a ligand? (2) What cell organelle does this ligand act on? OR (3) What ion is released into the cytoplasm as a result of the ligand's binding?

1-IP3, 2-smooth endoplasmic reticulum 3-

11. Say something about ion flow when acetylcholine binds to the nicotinic acetylcholine receptor.

sodium comes in and potassium goes out

12. Answer EITHER what is the term used for a drug that (1) mimics OR (2) blocks a receptor in the membrane?

agonist, antagonist

13. "Receptor mediated endocytosis" - Say something about EITHER (1) What is on the outside of the vesicle? OR (2) What is on the inside of the vesicle?

1-clathrin (that makes a coated vesicle look coated), 2-the receptor for what is being endocytosed plus what is being endocytosed like LDL or HDL

14. What molecule delivers the required energy to the sodium-potassium pump?


15. In discussing Ohm's law, what is the slope of the line when I (Y axis, ordinate) is shown as a function of V (X axis, abscissa)?

the conductance (g)

16. When Nernst assumed equilibrium, he assumed that the energies (say for potassium) in a two thermodynamic systems (say inside the cell vs outside the membrane) are equal. For each system (say inside the cell), there are two components, an electrical component and (what?)

a chemical component

17. Based on a careful analysis of how a Wheatstone bridge went out of balance while an action potential went by, what fundamental conclusion did Cole and Curtis make?

that the conductance increased during the action potential

18. When I inject current to depolarize an axon to the threshold for the action potential, the voltage swings up with an exponential curve (i.e. a delay). What property of the membrane causes this delay?


19. Suppose you had an axon where activation of the channels is blocked (hence no action potential, and only passive propagation). With an electrode, you create an action potential sized voltage at one location on this axon. Relatively, what size would the voltage be at some distance from the location where your spike voltage is?


20. In saltatory conduction, why does the action potential jump from one node of Ranvier to the next rather than fizzling along the axon.

myelin insulates between the nodes

21. Why, according to the idea of Experimental Autoimmune Encephalitis (EAE), do scars form in the brains of people with multiple sclerosis?

the immune system attacks the white matter

22. Why did Sherrington refer to the spinal motor neuron as the "final common pathway in the integrative action of the nervous system?"

it can integrate EPSPs and IPSPs while the motor end plate is only excitatory

23. Stimulating a nerve that inhibits the postsynaptic nerve does what to the electric potential of the postsynaptic nerve.

it becomes more negative (hyperpolarizes)

24. What makes it so that there are calcium ions to bind to synaptotagmin?

the action potential opens voltage gated calcium channels in the nerve terminal

25. Reuptake into the presynaptic terminal terminates the action of norepinephrine. By contrast, how is the action of acetylcholine terminated?

it is broken down by acetylcholinesterase to acetate and choline

26. For EITHER (1) an acetylcholinesterase inhibitor OR (2) poisoning with botulism toxin, how would the victim die?

1-heart would stop, 2-anything that required neurotransmission, like breathing, would stop

27. An ultraviolet (UV) light made my shirt look blue. How did this concept (fluorescence) relate to Parkinson's disease?

fluorescence microscopy was used to find the nigro-striatal dopamine tract

28. "Caffeine potentiates the action of epinephrine and norepinephrine." How (chemically)?

it inhibits the breakdown of cAMP, the "second messenger" by PDE

29. Why not just give dopamine to help patients with Parkinson's disease?

it does not cross the blood brain barrier

30. "The sympathetic nervous system is sometimes called the "thoraco-lumbar system." With similar reference to anatomy, what do we call the parasympathetic nervous system?


31. If you have a pathway from the central nervous system that eventually reaches beta-2 receptors at the effector (smooth muscle), answer EITHER (1) What is the neurotransmitter RECEPTOR at the GANGLION? OR (2) What is the TRANSMITTER at the NEUROEFFECTOR JUNCTION?

1-nicotinic cholinergic, 2-norepinephrine

32. Why would a beta-blocker help in the treatment of high blood pressure?

it should decrease the sympathetic (stress) increase in heart rate and heart contractility

33. Why is the word "belladona" used in reference to atropine?

women are more beautiful if they dilate their pupils as a cosmetic procedure

34. The dogma for a typical neurotransmitter is that it is (1) released from the presynaptic cell in vesicles and that (2) the neurotransmitter substance affects receptors in the postsynaptic cell's membrane. For EITHER (1) OR (2), contrast the situation for nitric oxide.

1-made on demand by an enzyme (eNOS), 2-crosses into "postsynaptic" cell to activate an enzyme (GC)

35. A string of sarcomeres stacked end-to-end going the length of the muscle is a unit called (what?)


36. Let's assume that none of you have Duchenne muscular dystrophy. What is your status with respect to the protein "dystrophin?"

you all have the normal form of the protein

37. "It's like myosin is rowing in a sea of actin." In a cycle described by (at least) 6 sequential steps, what happens when ATP binds into the pocket that had been vacated by ADP and phosphate?

myosin unbinds actin

38. How, and under what circumstances, does tropomyosin keep myosin from binding to actin?

it hides myosin's binding sites on actin unless calcium binds troponin

39. Why did Katz lower the extracellular calcium concentration at the neuromuscular junction in his Nobel prize-winning research that demonstrated that vesicles were the quanta of synaptic transmission?

he decreased the vesicle release to a distribution of 0, 1, 2, or 3 miniature end plate potentials

40. Why would neostigmine ameliorate the symptoms myasthenia gravis?

it would increase the amount of acetylcholine available to act on a decreased number of nicotinic channels

41. In addition to plasma free fatty acids and muscle triglyceride, name one caloric source of energy in muscle?

glucose (from plasma) and glycogen (in muscle)

42. Describe the transition in how tetanus looks (when muscle tension is graphed as a function of time) as the nerve stimulation is increased from a slow rate (5 shocks per second) to a faster rate (10 shocks per second).

when slow, tetanus is bumpy, revealing summation of visible twitches, but a steadier contraction is achieved with faster stimulation

43. What does the reaction of phosphocreatine to creatine achieve?

it generates ATP from ADP in muscle

44. What is the function of gamma motor neurons feeding to nuclear chain fibers (intrafusal muscle fibers) in the muscle spindle?

preset the stretch on the stretch receptor

45. Where did the calcium ions to mediate smooth muscle contraction come from?

they come into the cell from outside

46. What do varicosities in autonomic neurons do (where they are near smooth muscle cells)?

release neurotransmitter

47. When you start with one glycerol molecule and three fatty acid molecules, what do you get with the condensation (compound dehydration) synthesis?

a fat (triglyceride) molecule

48. When we use amino acids as an energy source, what becomes of the nitrogen?

converted to urea then eliminated

49. What is the net ATP production by the time two pyruvic acid molecules are made from one glucose molecule?

only 2 NET

50. During "fasting" (a few hours after a meal before the next meal) where does glucose come from to maintain blood glucose levels?

glycogen in liver

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last updated 9/26/2013