BIOL 2600 Human Physiology, Fall 2017, Prof. Stark
First Hourly Exam, Monday October 2, Short Answer

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

adrenal cortex

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

piloerection, vasoconstriction

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

untreated diabetes mellitus

4. 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

5. 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

6. 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

7. "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?


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


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

no, it is active b/c it uses ATP

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


11. 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

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

conductance, g

13. 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

14. 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

15. 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

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


17. "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?


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

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

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

a few, each glial cell myelinates a few axons

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


21. 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)

22. 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

23. What is the calcium binding protein of the synaptic vesicle?


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

slow it or stop it

25. 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

26. 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)

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

sodium and potassium

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


29. 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

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

to relieve depression

31. Why might a physician give a patient l-DOPA?

to relieve Parkinson's disease, precursor of dopamine

32. How does caffeine have its stimulatory effect?

blocks cAMP phosphodiesterase

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

inhibits parasympathetic meciated activation of gastrointestinal motility

34. How does Viagra work?

inhibit PDE to break down cGMP

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

muscarinic for acetylcholine

36. 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? or (2) What happens upon this release?

ADP power stroke

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

hemoglobin, myoglobin, cytochrome

38. 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

39. What is an intrafusal motor fiber?

presets stretch on spindle's stretch receptor

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


41. 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

42. 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

43. In what way does the source of calcium ions differ between smooth muscle and striated muscle?

from extracellular smooth, SR striated

44. What are varicosities with respect to control of smooth muscle?

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

45. 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

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

lactic acid

47. 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

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

ammonia (NH3)

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


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


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last updated 9/26/2017