BIOL 2600 Human Physiology, Fall 2017, Prof. Stark
Third Hourly Exam, Monday December 11, Short Answer

1. An osteoclast contributes to the regulation of blood calcium ... Answer either (1) under the influence of what hormone? (2) how?

parathormone, secrete HCl to break down calcium phosphate and enzyme to break down collagen

2. Upstream of a gene, there is a place where a steroid protein receptor combined with a steroid hormone binds. What is this area in the DNA called?

a response element

3. What female hormone is a precursor of testosterone?


4. What treatment has been standard for relief of hot flashes?

estrogen replacement therapy

5. The hormone T4 comes up to a cell's plasmalemma in the company of a carrier protein. Say something about what else is involved before that hormone might activate a gene's transcription.

converts to T3, binds receptor protein, that protein binds DNA, in the company of 9-cis retinoic acid bound to RXR receptor

6. What effect if any would castration have on the seminal vesicle?

it would be smaller

7. Why did COX-2 inhibitors show so much promise, and why were some pulled from the market?

relieve arthritic inflammation without interfering with gastric mucosa, increased chance of heart attack

8. Why would hyperplasia of the adrenal masculinize a female?

adrenal cortex makes anabolic steroids like testosterone, too much if there is hyperplasia

9. The enzyme 5-alpha-reductase is thought to be involved in androgenic alopecia. Answer either (1) What is androgenic alopecia? or (2) What product of 5-alpha reductase might contribute to androgenic alopecia?

baldness in men, dihydrotestosterone

10. After the zygote is first formed, but before implantation, some rudimentary development occurs. Answer either (1) What is the term used for these cell divisions? or (2) Where do they take place?

cleavage, uterine (fallopian) tube

11. In your textbook's diagram of the seminiferous tubule, cells called "spermatogonia" were shown. No analogous "oogonia" were shown in the diagrams of the ovary. Why not?

there are no oogonia after 3 months of age

12. A low PSA reading is around 1 while a high PSA is 5. What does PSA stand for?

prostate specific antigen

13. What is the "egg" called officially at the time of ovulation, and what stage of meiosis or mitosis is it in at that time?

secondary oocyte, before meiosis II is complete

14. What capability did embryonic stem cells possess that other cells lacked?

pluripotent or totipotent, can become any type of cells

15. What would have happened to a person who did not have Mullerian Inhibiting Factor (MIF)?

primordial "plumbing" would become uterus and uterine tubules

16. Considering how much fibrin is around when clotting is needed, how come fibrin does not make blood clot all the time?

unless cleaved by clotting cascade, fibrinogen is inactive

17. Why did AIDS, in the first few years, create a new "selection pressure" against hemophiliacs?

before AIDS, the "environment" was one where clotting factor was available through medical technology; after AIDS (before the blood banks were better secured) this factor from multiple blood donors had a grim chance of being infected

18. Why are lysosomes an important part of phagocytic leukocytes?

they merge with endosomes to digest them

19. Why is AB the universal recipient?

no A or B antibodies

20. Some bacteria come in through a small skin injury. How do phagocytitc cells get from an intact capillary to the site of the injury?

chemotaxis, slither between endothlial cells

21. 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

22. Class II MHC (major histocompatability complex) is expressed only on macrophages and B lymphocytes. What about class I?

all cells, involved in attack on infected cells

23. Which specific type of white blood cell is depleted in AIDS (acquired immunodeficiency syndrome)?

CD4-expressing (helper)

24. What kind of protein is the antigen receptor on the surface of a B lymphocyte?

antibody (IgD)

25. Axons for one sensory system are in the dorsal columns. Answer either (1) Where are these dorsal columns? Or (2) What is being perceived by this sensory system?

dorsal white matter of spinal cord, fine touch

26. In terms of localization of function of the cerebral cortex, what is the function of the postcentral gyrus?

somatosensory projection

27. Cells with sensory information make their synapses in the postcentral gyrus. Where are the cell bodies of these cells?


28. Where is the decussation (cross over) of the lemniscal system for localized touch?

in medulla

29. Where does the globus pallidus feed to?

to thalamus to motor cortex

30. How did they learn which parts of the body project to which parts of the postcentral gyrus?

gently stimulate the gyrus in a patient under local anesthesia ahd ask where (s)he feels a tingle

31. What would happen to the coding sequence of the mutant allele for Huntington's chorea from one generation to the next?

there would be more CAG's coding for more glutamines

32. In the vestibular system there are 3 fluid-filled (what) plus 2 organs with otoliths, the (what?) and the (what?). [Answer one of the above.]

semicircular canals, utricle & saccule

33. About how many different G protein coupled receptors are involved in human olfaction?


34. What is PTC (phenylthiocarbamide) and what did it reveal about sensory transduction?

a substance that tastes bitter and helped in the isolation of the G protein-coupled receptor

35. "Sound intensity is measured in log units." Be more specific than that.

dB is 20 log ratio of pressures

36. Tip links between stereocilia contribute to channels responsible for what kind of stimulation?

mechanosensation, or hearing, or balance, possibly K+

37. What is compared that would allow you to tell which side of your head a sound is coming from?

inputs from the two ears

38. Helmholtz proposed that different frequencies stimulated different places along the basilar membrane. In what way(s) was his place theory confirmed or contradicted?

true, but localization is crude, lateral inhibition corrects for this

39. How is it that K+ moves in, rather than out, through channels in auditory hair cells?

an unusual extracellular fluid (endolymph) is high in K+

40. Some animals can hear ultrasound. How does ultrasound differ from the sounds humans can hear?

it is a higher frequency, higher than 20,000 Hz

41. "A laser is used to destroy patches of the retina." Answer either (1) Who might actually benefit from this procedure? or (2) Why would the ophthalmologist avoid blasting the fovea with the laser?

a diabetic, fovea is too essential for high acuity color vision at the point of fixation

42. Why are you blind in your blind spot?

no receptor cells can be present where the optic nerve exits and the blood supply enters and exits

43. Which side of the retina projects to the ipsilateral thalamus (lateral geniculate body) at the optic chiasm?


44. What kind of lens corrects for myopia (near-sightedness)?


45. Other than serving as the "black paint" that keeps light from reflecting around the eye, state another function of the retinal pigment epithelium.

phagocytose shed rod disks, chemical reactions to replenish 11-cis-retinal

46. Why would we use the term "tunnel vision" for the blindness in retinitis pigmentosa?

rods in a circle around the point of fixation degenerate

47. Why are you unable to see ultraviolet light (while I can)?

the lens blocks UV, I had a lens removed

48. In phototransduction, the heterotrimeric G protein's alpha subunit activates an enzyme. For EITHER Drosophila OR humans, what is that enzyme?

phospholipase C or cGMP" PDE

49. "Vitamin A is the chromophore of rhodopsin." We get this vitamin A from what dietary precursor?

carotenoids like beta carotene

50. Say something about the garbage that accumulates in cells of the aging human eye.

called lipofuscin, autofluoresces yellow, in retinal pigment epithelium cells, from shed photoreceptor tips

return to syllabus

return to Stark home page

last updated 12/5/2017