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BIOL 260 Human Physiology, Fall 2008, Prof. Stark
Final Exam, December 10, Short Answer

1. The lay expression for ectotherm is "cold-blooded." Why is that inaccurate?

More like they assume ambient temperature

2. How come homeotherms (endotherms) always have heat available for maintaining body temperature at the set point?

Because of inefficiency in metabolism, waste is heat

3. In addition to triiodothyroxine, what is the other thyroid hormone?

T4

4. Under what circumstances (what do you do?) does a passive process (what process?) let you make a red blood cell ghost from a red blood cell?

Put r.b.c into distilled water, osmosis

5. Tell me about a famous lysosomal storage disease. Your answer can be biochemical, cell biological, or genetic.

Tay Sachs fails to break down a glycolipid that accumulates in the cell, autosomal recessive carried in Ashkenaze Jews

6. In the transmission electron microscope, what membrane specialization of receptor mediated endocytosis is visualized?

Clathrin coated pits (vesicles)

7. A deliberate slight of hand had me graphing Ohm's law with the X and Y axes reversed. Thus, we talked about "conductance" which relates to what way of describing how well ions traverse a membrane channel?

permeability

8. 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)

9. An oscilloscope presents the action potential like a graph. What are on the X and Y axes?

X time, Y voltage

10. Why was Golgi's technique, so exquisitely used by Ramon y Cajal, a contribution worthy of the Nobel Prize?

Among a zillion cells, one cell could be seen in its entirety

11. 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)

12. "There are no channel receptors for norepinephrine." Then how are these norepinephrine receptor proteins characterized?

GPCR

13. How is the color of the substantia nigra related to its role in distributing a transmitter through the brain?

Melanin is a polymer of DOPA, dopamine is a product of DOPA

14. A cell might depolarize or hyperpolarize even when a metabotropic receptor that is not an ion channel is activated. How can this be?

Through inhibitory vs excitatory G proteins (alpha subunits)

15. Explain how vasoconstriction (or the opposite) applies to how a decongestant unclogs a stuffed nose.

An alpha agonist like phenylephrine constricts engorged vascular bed

16. Striated muscle has an optimum length, and it's strength (tension) drops off when it is longer or shorter. In what way is the ventricular myocardial muscle strikingly different?

The fuller (more stretched) the ventricle, the more forceful the contraction

17. Why is a corpse at a crime scene referred to as a "stiff?"

When ATP runs out, actin stays bound to myosin

18. Why would neostigmine ameliorate the condition of myasthenia gravis?

Shortage of nicotinic channels is somewhat overcome if there is more ACh

19. What cell is deficient in Lou Gehrig's disease (ALS=amyotropic lateral sclerosis)?

Spinal motor neuron

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

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

21. What use is made of protons (H+, hydrogen ions) running back down their concentration gradient (after they had been pumped up that gradient)?

This is the "water turbine" to generate ATP

22. "Tyrosine kinase" - where did the phosphate come from?

ATP donates the phosphate there (and pretty much everywhere)

23. Amino acids can be used for catabolic energy. Where do they feed into the metabolic mill?

Into pyruvic acid just before acetyl co-A

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

Via cAMP, increase conversion of glycogen to glucose

25. What pancreatic hormone is increased during fasting?

glucagon

26. "ATP is the ligand that closes the K+ channel in the islet's beta cell." What does this do to the electrical potential?

depolarize

27. What effect does cortisol have on adipose tissue?

Cause release of free fatty acids

28. At the peak of systole, how does the pressure in the right ventricle compare with the pressure in the left ventricle?

Way lower pressure in pulmonary circulation

29. Both branches of the autonomic nervous system (sympathetic and parasympathetic) connect to both nodes of the heart(SA and AV). In addition, the sympathetic nervous system also makes additional connections to the heart (to where? Or for what purpose?).

to muscle to increase strength of contraction

30. What would happen to the Q-T interval during strenuous exercise?

shorten

31. What is the function of an arteriovenous anastomosis?

Shunt blood to bypass capillaries in skin to prevent heat loss

32. Why wouldn't you expect inhibitors of prostaglandin synthesis to help with inflammation in asthma?

Leukotrienes, not prostaglandins

33. Total lung capacity minus expiratory reserve minus inspiratory reserve minus residual volume equals what?

Tidal volume

34. What happens to the pressure in what compartment to cause the lung to collapse?

Intrapleural becomes equal to atmospheric

35. Other than the medulla (of the brain), where are there chemoreceptors to control ventilation? (or, if you prefer, tell me how they feed to the brain.)

aortic and carotid bodies

36. From the renal pelvis, the urine flows to the bladder via what tube?

ureter

37. Why is it advantageous to have hypertonic interstitial fluid in the kidney medulla?

Then, if ADH is present, water will be salvaged from the collecting duct

38. Why would it be advantageous to position renin secreting cells where they are?

Blood pressure is monitored near the glomerulus for the emergency work of angiotensin that rennin initiates

39. For glucose absorption from the gut, what is the process on the basolateral surface that requires energy?

The sodium pump

40. Sometimes endopeptidases will cut off fragments that are two amino acids long. What becomes of these?

41. "In histology, you see zymogens located in acinar cells." What does that have to do with digestion?

These granules house the precursors of digestive enzymes of the pancreas

42. Relate the hepatic portal vessel with the "microsomal fraction" (smooth endoplasmic reticulum of the hepatocyte).

This gives the liver a chance to detoxify what is absorbed from the gut before it gets to the systemic circulation

43. "A lesion in the lateral hypothalamus (LH) gives you a thin rat, hence the LH is a hunger center." What have we learned since this conclusion was first reached that gives us a different view of the role of the LH?

The LH has the dopamine tract that is useful in motivation (affect) in general

44. What is it called when a hypothyroid condition as an infant leads to deficient neural development?

cretinism

45. What is the condition where there is too much ACTH? - Answer one: (1) name of condition (2) What is there too little of? Or (3) Why does the skin get dark?

Addison's disease, too little cortisol, ACTH is like MSH (melanocyte stimulating hormone)

46. The adrenal cortex is famous for producing androgens, glucocorticoids and (what else?).

mineralocorticoids (aldosterone)

47. Norepinephrine is converted to epinephrine to be the major hormone of what (specific) gland.

Adrenal medulla

48. Why would cod liver oil be a useful dietary supplement for some people?

Vitamin D

49. Why was there the conventional wisdom that estrogen by patch was safer than oral administration?

Swallowed, the liver could make many other products

50. Why was the women's health initiative study discontinued?

Increase in breast cancer, coronary heart disease

51. For "androgenic alopecia" tell me either (1) what these words mean, or (2) what an enzyme or the hormonal product it catalyses has to do with that.

Male pattern baldness, 5 alpha reductase makes DHT

52. How do the mitochondria in the sperm cell contribute to the DNA in the zygote?

They do not

53. Two meiotic divisions in the female result in only one "egg." What did the other nuclei produced by meiosis become?

Polar bodies

54. In cloning Dolly, an egg was obtained, its nucleus was removed, a somatic cell nucleus was put in, and cell divisions create an embryo (a hollow ball of cells) in vitro. What did they have to do after that so that a sheep was born?

Implant into a surrogate mother

55. Why would the intrauterine device (IUD) be considered to be particularly controversial?

Well, even blocking fertilization might be controversial, but blocking implantation is a really early abortion

56. Why does in vitro fertilization come up in discussions of the benefits and controversities of stem cell research?

One possible source of embryonic stem cells would be "left overs" once a couple has decided they have had enough children

57. How would a blood count help to determine if you had a systemic bacterial infection?

There are more neutrophils in bacterial infection

58. Explain what agglutination is using transfusion of type A blood into a type B recipient as your example.

Antibodies would cause red blood cells to clump together

59. How can your immune system (conceivably) develop antibodies to every possible epitope?

The genes themselves get spliced to make the many variable regions

60. Class 2 MHC on the surface of an antigen-presenting macrophage acts in conjunction with (what?) on the surface of a helper T cell to activate it.

CD4

61. WHY (note, I am just asking why) would a half spinal cord lesion affect senses mediated by spinothalamic vs lemniscal systems below the injury differently?

Where they cross over is different, spinothalamic below the lesion, lemniscal above

62. How was the map of the postcentral gyrus obtained?

Gently electrically stimulate and ask the person where (s)he feels it

63. "The thalamus is a relay (more than a relay!) for sensory and motor systems." And yet the corticospinal tract went right past the thalamus without making a synapse. In what system, then does the thalamus have motor synapses?

Estrapyramidal - basal ganglia feed back to motor cortex via thalamus

64. On the back of the tongue, taste buds are found on what larger structure (hint, nine of them, and the nerve projects by the IX cranial nerve, the glossopharyngeal).

Circumvallate papillae

65. In terms of the respective molecular biology of transduction, why is olfaction a much richer sense than taste in humans?

There are maybe a thousand receptors for different primaries

66. Movement of the organ of Corti relative to (what adjacent membrane?) causes the "cilia" of auditory hair cells to bend.

tectorial

67. K+ comes in through the auditory cell channel. Now, wait a doggone minute. How did that happen?

b/c K+ is high, which is unusual, in the extracellular fluid (endolymph)

68. The eye pressure is high. Answer either (1) What isn't draining properly? (2) Death of what cell type would mediate vision loss? Or (3) What is this condition called?

Aqueous humor, ganglion cell, glaucoma

69. Why would a person with my interests need to use Planck's constant?

Since it gives energy of a photon, it can assist in calculations of light intensity

70. When an ophthalmologist looks at your retina, what is the second most conspicuous landmark after the optic disc?

Macula (fovea)

71. What does the Mary Lyon X inactivation hypothesis have to say about heterozygous carriers of red or green colorblindness (both of which are on the X)?

It should not be a matter of dominant vs recessive, but her retina must be a mosaic

72. What is it that allows the sodium channel in the rod outer segment close?

Removal of cGMP by phosphodiesterase

73. In the visual projection, where is the first place where inputs from both eyes can connect to the same cell?

Not until the cortex

74. What is lost making people with age related macular degeneration (AMD) blind?

Cone (foveal) vision

75. The photopic (cone-mediated) spectral sensitivity is lower (especially in the blue) on-fovea than off-fovea. Why?

That's where macular pigments absorb blue light


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