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BIOL 260 Human Physiology, Fall 2009, Prof. Stark
First Hourly Exam, October 30, Short Answer
1. For insulin, answer either (1)Why would you need to inject it (i.e.,
why can't you take it by mouth? (2) How does it look relative to the precursor
molecule from which it is made?
proteins would be digested, larger protein was clipped to 2 fragments bound
with disulfide bonds
2. Why does laser photocoagulation slow the progress of diabetic retinopathy?
decreases angiogenesis signal
3. Gluconeogenesis would result from what change in the ratio of insulin
and glucagon?
I/G low, i.e. glucagon mobilizes new glucose formation formation
4. Beyond its function as the "currency for energy," what important
function does ATP have in the beta cell of the islets of Langerhans?
intracellular ligand, ultimately for insulin release
5. By what molecular mechanism does cAMP activate protein kinase A (A-kinase)?
2 cAMPs each bind 2 inhibitory subunits to activate 2 catalytic subunits
6. What is the status of bicuspid and tricuspid valves during diastole?
open and blood gushes from atria to ventricles
7. "Fenestrated endothelium." Explain either (1) fenestrated or
(2) endothelium.
windows (holes) in layer that lines blood vessels (capillaries
8. How would nitroglycerine give you relief?
relax smooth muscle, coronary arteries more patent to relieve angina
9. Why does blood flow more slowly in capillaries than in arteries?
there is a greater cross sectional area
10. Why do the atria contribute only minimally to the ventricular filling
during diastole?
because blood flows to ventricles during diastole b/c A-V valves are open
11. Even before ventricular pressure overcomes arterial diastolic pressure,
increasing ventricular pressure does (what?) to (what valves?).
snaps shut A-V valves
12. What did pumping the blood pressure cuff up to 140 mmHg do? (Assume
you have a subject with fairly normal blood pressure.)
close brachial artery
13. "The heart is an electrical syncitium" because of what specialization?
gap junctions
14. What is the channel critical for diastolic depolarization (pacemaker
potentials)?
HCN hyperpolarization cyclic nucleotide
15. Why would you prescribe an inhibitor of angiotensin converting enzyme
to a patient?
decrease blood pressure
16. What is the difference between plaque and a thrombus in arterial occlusion?
plaque builds up in artery wall b/c of cholesterol, thrombus is blood clot
17. What would have to be wrong with a patient to warrant shocking the chest
with paddles and why would that help?
ventricular fibrillation, i.e., heart electrical activity flat lines
18. "Mucus elevator." Relate to the conventional wisdom about
the interaction of asbestos and smoking.
smoking paralyses cilia so asbestos gets stuck in lungs worse
19. What would the sympathetic nervous system do to the air passageway opening?
open
20. The partial pressure of O2 in the atmosphere is 159 mm Hg. Give a reason
it is much lower in the alveoli.
lowered b/c water and CO2 are high
21. You are studying the respirometer record of a patient. What is the one
volume you cannot ascertain from this record?
residual
22. Why might a lung collapse from a piercing stab wound to the chest?
intrapleural pressure becomes atmospheric pressure
23. Why does surfactant make breathing easier?
decreases surface tensiol
24. What information is carried from the aortic and carotid bodies to the
brain to control breathing?
acidity
25. How does the ionization of carbonic acid into H+ and HCO3- in the red
blood cell greatly increase the amount of carbon dioxide that can be transported?
then bicarbonate can be sent to the large volume of the plasma
26. In describing the work of the kidneys, some relevant volumes were graphically
described in terms of drums containing 55 gallons. Why were there 32 and
8 drums in that story?
32 volume of blood pumped daily, 8 through kidneys
27. "A disruption in the Humboldt current might have an effect on bird
droppings." Fill in a few of the details missing in that telegraphic
statement.
bird droppings - uric acid, nitrogen fertilizer, birds eat anchovies which
thrive b/c of Humboldt driving upwelling
28. In the portal system of blood flow in the kidney, describe the anatomical
localization of the second capillary bed (vasa recta).
surrounds each loop of Henle in medulla
29. In addition to foot processes (pedicels) of podocytes, how else is a
fine-mesh mechanical sieve achieved in the glomerulus?
fenestrated endothelium
30. Why would an adrenalectomy cause an animal to have a specific appetite
for salt?
loss of aldosterone makes kidneys lose salt
31. What change of appetitive behavior would accompany an increased secretion
of ADH (antidiuretic hormone)?
while kidneys wold conserve water, you would also be thirsty
32. For hormonal control originating from the juxtaglomerular apparatus,
answer either (1) What purpose does it serve? Or (2) Why is the location
of the juxtaglomerular apparatus ideal for monitoring this need?
emergency response to low blood pressure, near afferent arterioles
33. Make an argument that salivary amylase is not of significant value in
the overall hydrolysis of macromolecules for digestion.
swallow soon and inactivated in stomach
34. At what structure is gastric emptying controlled.
pyloric sphincter
35. "Proteins are broken down into amino acids and that is what is
absorbed." Why is this not the whole truth regarding the apical surface
of the intestinal epithelial cell?
uptake of di and tri peptides
36. Why is jaundice one sign of hepatitis?
b/c bile pigments build up in blood
37. "Everybody knows about (what structure that feeds blood from the
small intestine to the liver?) if they took a course like this."
hepatic portal vein
38. What are the products when lipase acts on triglyceride in the lumen
of the small intestine?
2 fatty acids and monoacyl glycerol
39. With the G cell, the ECL cell, histamine, amino acids, and the vagus
nerve, answer either (1) What hormonal system?, (2) That hormone affects
what cell type? Or (3) That cell type releases what?
gastrin, parietal, HCl
40. Homozygous obese (ob/ob) p; Answer either (1) What is the protein
product of that gene that is missing? Or (2) What tissue releases this product
(in non-mutant mice)?
leptin adipose
41. "If the mother plans to breast feed, it is useful to give her the
baby to suckle right after delivery" for what endocrine reason?
to retract uterus
42. In what way would growth be different if there were too much growth
hormone as a child vs. too much growth hormone as an adult?
bones get longer vs thicker
43. In addition to its negative feedback control on the hypothalamus/pituitary,
what effect does estrogen have on the endometrium?
build up
44. "The pill" p; one a day for 28 days: Why would women
still menstruate?
estrogens - build up of endometrium, duds, let it break down
45. In addition to triggering ovulation, a surge of LH does what (to the
endocrine structure/function of the ovary)?
follicle changes to corpus luteum
46. Once human chorionic gonadotropin "takes over," what is the
status of FSH and LH release by the pituitary?
they are still not released, inhibited by progesterone
46. Once human chorionic gonadotropin "takes over," what is the
status of FSH and LH release by the pituitary?
progesterone from the still functioning corpus luteum still inhibits Pituitary
FSH and LH
47. Estrogen and thyrocalcitonin (calcitonin) would affect bone, answer
either (1) With what cell type? Or (2) In what way (would they affect bone)?
osteoblasts, put in calcium
48. In the old days, some people would have had rickets. What aspect of
their life style (discounting diet) would have led them to have gotten this
disorder while other people would not?
winter, clothing, sun avoidance
49. Name a precursor of estradiol-17b.
testosterone, progesterone, cholesterol
50. "Steroid hormones affect transcription of certain genes. How?
bind receptor protein that binds response element
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