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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?

occipital

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 detail?

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.

kinesin, tubulin

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 action potential?).

myelin

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?).

capacitance

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 out)

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?

sodium

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 channel?

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+?

vitamin D

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

vagus

36. A patch with hexamers in register between two adjacent cells describes what kind of intercellular communication structure?

gap junction

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 place?

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?

it hyperpolarizes

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 synaptic transmission

41. Name a protein involved in retrieval of vesicle membrane.

clathrin dynamin

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?

agonist

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?

enzymes

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 in neurotransmission?

metabotropic receptors like the muscarinic acetylcholine receptor are 7 transmembrane spanning G protein linked receptors that signal to this G protein.

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 it produces?

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 ganglia?

same

52. One portion is called thoraco-lumbar. What is the equivalent name for the other portion (of the autonomic nervous system)?

cranio-sacral

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 toxin

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 and Zoloft)?

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?

melatonin

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?

GABA

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 is everywhere

62. Receptor antagonists for what transmitter are considered to be the most effective treatment of schizophrenia?

dopamine

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 electrical term?
 
 conductance
 
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?

ms

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