1. In the knee-jerk reflex, the flexor is inhibited. How?

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

2. Confocal microscope. Answer either (1) How did they make tau look red and tubulin look green in that textbook micrograph? or (2) What property of the technology allowed Dr Stark's student make a Quicktime movie focusing through the depth of the Drosophila retina?

bind green- or red-emitting fluorophores to secondary antibody that binds primary antibody to tau and tubulin, optical sectioning = low depth of focus

3. In the 1800's, Broca delineated a brain area critical for speech. How did he do this?

after death, on autopsy, he saw brain damage in a patient with damage to his speech

4. If a thrombus occluded one internal carotid artery, the brain damage might not be immediately devastating because of what anatomical specialization

circle of Willis

5. Neuroscience class alumnus did some imaging work at Washington University to show that people who were blind from an early age had diminished tracts ANSWER EITHER (1) from where OR (2) to where?

thalamus (lateral geniculate nucleus), visual cortex (area 17)

6. In explaining fluorescence, why is the emission a longer wavelength than the excitation?

energy is lost before a photon is re-emitted

7. How was Ramon y Cajal able to produce pictures of neurons in intricate detail?

Golgi's technique fully stained one cell. Since surrounding cells were not stained, he could draw the ones that were stained

8. 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

9. In the neurons and glia lecture, we referred to two components of the blood brain barrier between the blood and the cerebrospinal fluid. Identify one of these.

capillary endothelium plus astrocyte end foot

10. Why, in the transmission electron microscope, does myelin look so dark?

membranes bind osmium (and it is electron dense) and myelin has many layers of membrane

11. Why did Charcot-Marie-Tooth disease patient JH show you his calf?

the motor neuron loss in his peripheral neuropathy would result in a loss of muscle

12. Why is myelin such a good insulator?

the many membrane layers add resistors and the capacitance adds reciprocally

13. "Multiple sclerosis is an autoimmune disease." ANSWER EITHER (1) To what protein? OR (2) How can you get immune to a protein that belongs in your body?

myelin basic protein, its sequestration from immune surveillance has been compromised

14. What is the explanation for CMT subject JH not knowing that he ruptured his Achilles tendon?

loss of sensation

15. "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 out)

16. In the Goldman equation, concentrations (in and out) of sodium, potassium and chloride, and permeabilities for all three ions, are shown. There is an equivalent circuit (with electrical components) for the Goldman equation. What is used in the circuit model for the sodium permeability? Be thorough enough in your answer to address what happens to sodium permeability during the action potential.

a variable resistor (potentiometer) that lets sodium permeability go up

17. A large enough square wave injection of current depolarizes the axon to the threshold of the action potential. What do you call the voltage response to an injection in the other direction across the membrane?


18. Why would you want to inhibit the sodium pump in heart muscle cells with digitalis?

it would increase contractility by increasing intracellular calcium by altering a Na+ / Ca2+ exchanger

19. What is assumed in the derivation of the Nernst equation?

the energies of the two compartments are equal, alternatively that the chemical potential is equal and opposite to the voltage

20. "A line describes Ohm's law when it is graphed with current on the Y axis and voltage on the X axis." What is the slope of the line?


21. "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

22. You remove both adrenal glands of a rat and let it recover. Answer either (1) What is different about the animal's specific appetite? Or (2) This is explained by the absence of what hormone?

craves salt (NaCl) b/c of loss of aldosterone

23. 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

24. What does the space constant and the time constant have to do with why squids have giant axons?

cable equation's space constant varies with the square root of the radius while the time constant is independent of the radius, and the space constant over the time constant of passive spread ought to predict the action potential speed

25. "Sodium flows in during the action potential." Why then does sodium flow out when voltage is clamped to +65 mV (inside relative to outside)?

the voltage is clamped beyond the sodium equilibrium potential

26. 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

27. "The action potential depolarizes the axon ahead of it to threshold and thus generates an action potential ahead of it." Why doesn't it generate an action potential behind it?

there is a refractory period because the sodium channels are inactivated

28. "Cole and Curtis's bridge went out of balance." What did we learn from their 1939 work on the squid giant axon with the Wheatstone bridge?

conductance goes up as the action potential passes

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. 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 channel?

a chloride channel

31. Describe the structural or molecular specializations that form an "electrical synapse."

in gap junction, connexons are formed from hexamers of connexins in register from one cell to the next

32. The resting potential is -60 mV inside negative. Regarding the reversal potential for the IPSP, ANSWER EITHER (1) About how many mV is it? OR (2) What would happen to the membrane potential if clamped beyond the reversal potential upon activation of a GABA synapse?

1 -70 mV, it would depolarize instead of hyper polarizing

33. "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 place?

there is excitation, no inhibition, on the muscle cell

34. CSNB (congenital stationary night blindness): ANSWER EITHER (1) What cells do not work? OR (2) Why is it called "stationary?"

rods, it is not progressive (degeneration) rather blind from birth

35. Why would pheochromocytoma (PC) cells be a reasonable model for studying neurotransmitter release?

can culture adrenal medulla cancer cells which release catecholamines

36. What nerve did Otto Loewi from Austria use in the first demonstration that a neurotransmitter substance was used in signaling?


37. 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 synaptic transmission

38. Describe either the freeze-fracture or the transmission electron microscope image of a vesicle in the process of release.

holes (pits), omega figures

39. Regarding synaptic vesicles, ANSWER EITHER (1) Why is there paralysis when temperature sensitive Shibire mutant Drosophila are moved to the restrictive temperature? OR (2) What protein is coded for by the Shibire mutant?

1 vesicle membrane fails to recycle, 2 dynamin

40. What is meant by the term "putative neurotransmitter?"

it is probably a neurotransmitter but it is not proven to everyone's satisfaction

41. Why do you need to really cook the tomatoes and the mason jars?

to kill the endospores of the bacterium that makes botulinum toxin because the bacteria would grow in anaerobic conditions

42. For a deep, dirty puncture wound in the finger, ANSWER EITHER (1) Why would you want to try to make it bleed? (2) What would you want to look into when you hurry off to your family doctor?

"wash" the anaerobic bacterium out, have you had your tetanus booster in the last 10 yrs

43. For synaptic vesicle release, ANSWER EITHER (1) How did calcium ions come to be in the neighborhood? OR (3) What protein does it bind to?

1 came in through a calcium channel, 2 synaptotagmin

44. Opium is not a neurotransmitter. Name an endogenous molecule functionally related to opium that is a transmitter.

endorphin or enkephalin

45. Blocking the muscarinic cholinergic receptor on the heart with atropine would save your life if you were poisoned with what class of molecules?

acetylcholinesterase inhibitors

46. Why does it make sense that a monamine oxidase inhibitor could serve as an antidepressant?

potentiates noradrenergic transmission

47. Why are erectile dysfunction medications contraindicated if you are taking nitrates for chest pain?

there would be an unsafe drop in blood pressure

48. Why is it relevant that the substantia nigra is pale in Parkinson's disease?

l-DOPA is a common precursor of melanin and dopamine

49. One portion is called cranio-sacral. What is the equivalent name for the other portion (of the autonomic nervous system)?


50. Nitric oxide (NO) had previously been called "endothelial derived relaxation factor." What was relaxed?

smooth muscle in arterioles of the corpus cavernosum

51. What type of neurotransmitter receptor is used at sympathetic and parasympathetic ganglia?

nicotinic acetylcholine receptors, ionotropic, ligand-gated channels

52. Melatonin... (answer either) (1) ...is synthesized from what transmitter? Or (2) ...is synthesized in what part of the brain?

(1) tryptophan (2) pineal

53. "Reuptake into the nerve terminus terminates the synaptic action of glutamate." How else is glutamate's action terminated?

it is also taken up into glia

54. Haloperidol and chlorpromazine are antipsychotics because they are antagonists of what molecules?

dopamine receptors

55. In order to produce hamsters with large vs small testes, what did the lab prep technician need to do ahead of time?

put some on cycles of 8 hrs lights on vs 16 off and vice versa for the others

56. What is the mechanism of action of the antidepressant Prozac?

it is a selective serotonin reuptake inhibitor

57. What would happen to most of the l-DOPA given to a Parkinson's patient?

it would get decarboxylated before it crossed the blood brain barrier

58. "The lateral hypothalamus must be a hunger center since lesioning it makes the rat lose weight." What is a more modern explanation?

there is a generalized loss of motivation (affect) since the nigro-striatal dopamine tract in the median forebrain bundle which is lesioned

59. "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

60. What is in the tail of Torpedo that made it useful for cloners interested in the nervous system?

lots of tissue with acetylcholine receptors

61. What (or where) is the precursor for the endogenous cannabinoids?

membrane phospholipid
62. Why might a patient be given low doses of neostigmine?

increase the amount of ACh to stimulate the diminished number of nicotinic receptors in myasthenia gravis

63. There are not any channel receptors for (name ONE transmitter).

dopamine, norepinephrine

64. "Tritiated naloxone binds to places in the brain and is displaced by (what?) in parallel with their strength.


65. Why do you need to be very careful when you use muscle relaxation in conjunction with anesthesia?

while it is important for your patient or your research animal not to move, you must not paralyze without blocking pain

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last updated 2/10/17