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BIOL 415 Nerve cell mechanisms in behavior
BIOL 615 Neural bases of behavior
Test 1 Feb 17, 2011 - Prof Stark
All questions are short answer. 65 points total
1. A specialized brain scan technique shows a defect in a pathway in blind
subjects. What lobe does this tract go to?
2. The cells that make axons that project from the eye to the brain are
called ganglion cells. WHY is this nomenclature not correct?
"ganglion" is a term applied to the peripheral nervous system.
the retina is considered to be central nervous system
3. The caudate, putamen and globus pallidus receive input that is deficient
in Parkinson's disease. What is the overall function of this system.
smoothening out motor movements
4. In the knee-jerk reflex, the flexor is inhibited. How?
through an inhibitory interneuron in the gray matter of the spinal cord
5. How was Ramon y Cajal able to produce pictures of neurons in intricate
Golgi's technique fully stained one cell. Since surrounding cells were not
stained, he could draw the ones that were stained
6. "Histochemical fluorescence was used in the 1960's to trace the
dopamine tracts from the substantia nigra." Answer either (1) What
was it that fluoresced? Or (2) How did they (researchers in the 1060's)
determine these tract pathways?
(1) dopamine (reacted chemically) (2) histological sections allowed following
the tracks that fluoresced
7. "A secondary antibody, a goat anti-mouse IgG, is attached to a fluorescent
label like fluorescein." Answer either (1) What kind of a microscope
would you use? Or (2) What kind of molecule would the primary antibody attach
to? Or (3) Where is this molecule that the primary antibody attaches to?
(1) fluorescence or confocal microscope (2) the protein you wanted to stain
(3) on a microscope slide with a slice of the tissue being studied
8. "Major and minor dense lines alternate in the layers of myelin."
Answer either (1) What makes up the major line? (2) What makes up the minor
line? Or (3) What is meant by dense?
(1) the two intracellular membrane sides (2) the two extracellular membrane
sides (3) electron dense, dark in a transmission electron microscope
9. Spines express actin that is visualized by microscopy. Answer either
(1) Where is a spine? (2) Functionally, what kind of membrane does it have?
(1) on the dendrite (2) postsynaptic
10. The concept of the motor unit, all the muscle cells innervated by one
spinal motor neuron, was introduced. How is that muscle unit related to
Halstead's proposal on how he had some recovery after polio then the symptoms
recurred later in life.
new muscle cells were recruited to units innervated by surviving neurons,
but, by middle age, these new sprouts are lost
11. When radioactive proline (an amino acid) was put in the eye, it was
incorporated into a protein, and this protein was later found in the brain.
Name an axonal protein that was involved in this transport.
12. Something more than the endothelial cell is proposed to be responsible
for the blood-brain-barrier that makes the cerebro-spinal-fluid a privileged
compartment. What is the additional cell type?
astrocyte (glial cells)
13. "Thimerosal was removed from childhood vaccines in 1999."
Answer either (1) What is thimerosal? Or (2) This argues against thimerosal
being a cause of (what disorder?).
(1) a mercury-containing preservative (2) autism
14. I showed you a figure that indicated that channels mediating the action
potential were concentrated in small localized areas along the axon. What
are these places?
nodes of Ranvier
15. When an invertebrate needs a fast action potential, it has a giant axon
because it lacks (what specialization that vertebrates posess to speed the
16. A micropipette is touched to the membrane but not inserted into the
cell. Answer either (1) What is this technique called? Or (2) What would
it allow you to do?
(1) patch clamp (2) record current from individual channels
17. When a square wave of current is injected into the cell, the Voltage
change is gradual because of (what property of the membrane?).
18. Cole and Curtis showed that a bridge went out of balance in the squid
giant axon as the action potential went on by. What fundamental conclusion
did they draw from this?
resistance went down (conductance up)
19. "Theoretically, sodium should not flow in when the sodium channels
open." Answer either (1) Whose theory? Or (2) Why not?
(1) Nernst (2) chemical and electrical gradients equal and opposite
20. "If I could wave a magic wand and instantly abolish the sodium
potassium pump while I had an electrode in the cell," Answer either
(1) Why would the membrane potential NOT change a lot (immediately)? Or
(2) Why WOULD the membrane potential change immediately by just a few mV?
(1) gradients were established and would not run down quickly (2) the electrogenic
sodium pump is based on the imbalance (3 sodium ions in to 3 potassium ions
21. "Inside a Ca2+-sequestering cistern inside a cell is sort of like
outside the cell." For these two compartments (inside, say, sarcoplasmic
reticulum and extracellular fluid), how does the Ca2+ concentration relate
to the cytoplasmic calcium ion concentration?
calcium outside the cell is higher than in cytoplasm
22. In an experimental validation of the theory, it was shown that the slope
equals 58 mV per 10-fold change in K+ gradient. After the researchers had
an electrode measuring the resting potential, what did they do?
change the extracellular potassium ion concentration
23. Variable resistors are in an equivalent circuit model of the Goldman
equation. Which resistor is changed, and in what direction, at the start
of the action potential?
the sodium resistance is decreased
24. Aldosterone sensitive neurons mediate an animal's specific appetite
for what important substance relevant to action potentials?
25. "The time constant is independent of radius." Then why are
giant axons faster?
the space constant relates to the square root of the radius
26. Current goes down the axoplasm from the location where the action potential
is located. The amount of current gets smaller as a function of distance
from the action potential. Why does it get smaller?
it leaks out through membrane resistance and capacitance
27. In a Voltage clamp experiment, on the I-t curve, there is an early inward
current unless the voltage is clamped (at about what level?).
the sodium eauillibrium potential (+55 mV)
28. Why was it useful to obtain conditional mutants (like temperature- or
ether-sensitive mutants), rather than ordinary mutants, to isolate genes
like shaker and ether-a-go-go in Drosophila?
channelopathy mutants would be lethal
29. Why would long QT syndrome interfere with the body's response to stress?
can't get the heart beats short enough to speed up the heart rate
30. What part (domain) of the Shaker protein is responsible for inactivation?
a stopper (ball of amino acids) at the N-terminal end
31. Although it is thick mucus in the lungs that is life-threatening in
cystic fibrosis victims, it is a channel that is deficient. What kind of
a chloride channel
32. What causes the S4 transmembrane span of the sodium channel to rotate?
detection of the depolarizing voltage
33. Why was Electrophorus electricus useful in channel research?
sodium chasnnels were so plentiful in the electric organ that they could
be isolated and characterized
34. Parathormone, calcitonin, and (what other hormone?) help to maintain
appropriate levels of blood Ca2+?
35. What nerve did Otto Loewi from Austria use in the first demonstration
that a neurotransmitter substance was used in signaling?
36. A patch with hexamers in register between two adjacent cells describes
what kind of intercellular communication structure?
37. "The spinal motor neuron is the final common pathway in the integrative
action of the nervous system." Why is the spinal motor neuron (as opposed
to the muscle cell) the final place where integration of signals can take
there is excitation, no inhibition, on the muscle cell
38. Starting at a normal resting potential (not voltage-clamped), what happens
to the membrane potential of the postsynaptic cell if a GABA-releasing presynaptic
cell is activated?
39. A micropipette that was used to selectively inject chloride ions into
neurons told us (what) about postsynaptic potentials?
IPSPs are based in part on an increase in chloride conductance
40. In Sir Bernard Katzís Nobel Prize-winning research, he turned
end plate potentials into 0, 1, 2, or 3 miniature end plate potentials.
Answer either (1) How? Or (2) Why?
(1) by decreasing calcium ions (2) to show that vesicles were the unit of
41. Name a protein involved in retrieval of vesicle membrane.
42. After calcium ions come in through channels in the presynaptic membrane,
it binds to a calcium-binding protein to mediate vesicle release. Answer
either (1) What is its name? or (2) Where is it (which specific compartment
involved in vesicle release)?
(1) synaptotagmin (2) bound to vesicle membrane
43. What is the general term for a pharmacological agent that mimics the
action of an endogenous neurotransmitter?
44. For peptide transmitters, it is thought that vesicles are transported
out the axon. In contrast, what goes out by anterograde axonal transport
for small molecule transport like amines?
45. Opium is not a neurotransmitter. Name an endogenous molecule functionally
related to opium that is a transmitter.
endorphin or enkephalin
46. You were introduced to the function of the small G protein ras.in vesicle
release. In contrast, how is the larger, heterotrimeric G protein involved
metabotropic receptors like the muscarinic acetylcholine receptor are 7
transmembrane spanning G protein linked receptors that signal to this G
47. Reuptake is the standard mechanism for the termination of neurotransmitter
action. In contrast, how is the action of acetylcholine terminated?
breakdown by acetylcholinesterase
48. To study what type of neurotransmitter did a neuroscience course alumna
use pheochromocytoma (PC) cells?
49. Why is the color of the substantia nigra related to the neurotransmitter
DOPA is the common precursor of melanin and dopamine
50. Potentiating the action of (what?) is the rationale for the use of inhibitors
of MAO (monamine oxidase) as antidepressants.
since norepinephrine is not metabolized, there is more of it
51. Acetylcholine and nicotinic receptors are used in parasympathetic ganglia.
What transmitter and transmitter receptor would you find at sympathetic
52. One portion is called thoraco-lumbar. What is the equivalent name for
the other portion (of the autonomic nervous system)?
53. Where does the nitric oxide (NO) responsible for smooth muscle relaxation
come from? (cell type or enzyme)
endothelium, eNOS (endothelial nitric oxide synthase)
54. Cyclic GMP's breakdown is inhibited by what drug (or class of drugs)?
Viagra (Levitra Cialis) ED meds
55. SNARE: Answer either: (1) Give another name for one of the SNAREs or
(2) Name a clostridial toxin that cleaves one of the SNAREs.
(1) v-SNARE = synaptobrevin / VAMP t-SNARE = syntaxin (2) botulism, tetanus
56. "Now that there are antidepressants, there is no reason to be depressed."
Then why is there so much controversy about drugs like Prozac (and Paxil
some critics implicate them in increased risk of suicide or homicide
57. Melatonin... (answer either) (1) ...is synthesized from what transmitter?
Or (2) ...is synthesized in what part of the brain?
(1) tryptophan (2) pineal
58. "Testes of short day hamsters are smaller than testes of long day
hamsters" because of what hormone?
59. For glutamate and GABA, what mechanism supplements reuptake into the
nerve terminal to terminate the action of the transmitter?
reuptake into glia
60. GHB (gamma hydroxy butyrate, the infamous date rape drug) is related
to transmission by what neurotransmitter?
61. Why does it take a lot of DOPA to treat Parkinson's disease?
very little is available to cross the blood brain barrier because the decarboxylase
62. Receptor antagonists for what transmitter are considered to be the most
effective treatment of schizophrenia?
63. "People on lithium treatment might have smaller action potentials."
Answer either (1) Why would some people be given lithium? Or (2) Why would
their action potentials be expected to be smaller?
(1) to treat the manic phase of manic depression (2) b/c, since lithium
does not get pumped out, the gradient of cations seen by the sodium channel
is not normally steep
64. Permeabilities to 3 relevant ions are in the numerator and denominator
of the Goldman equation. Permeability is a chemical term. What is the analogous
65. The brain of a 55 year old comes to you for autopsy. You find numerous
scars in the white matter. What disorder do you suspect?
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