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BIOL 260 Human Physiology, Fall 2010, Prof. Stark
Second Hourly Exam, October 27, Short Answer
1. Insulin is made from a prohormone. State one of the things that are done
to make insulin from this prohormone.
A peptide fragment is removed from between the 2 that are part of insulin
and these are linked by 2 disulfide bonds
2. The long term health of a person with type 1 diabetes is best if the
right amount of insulin is given, keeping the person's blood sugar just
above the level that would result in coma. What would happen if less than
that amount of insulin were injected one time?
the blood glucose would not be quite as low, that's all
3. Answer either (1) for gluconeogenesis, where did the glucose come from?
Or (2) for ketogenesis, where did the ketone bodies come from?
1 from amino acids, 2 from triglycerides
4. Suppose there were a new substance, a potential drug or poison, that
depolarized all the beta cells in your islets of Langerhans. What do you
expect would happen if you tested this substance on an animal?
more insulin release, lower blood glucose, maybe coma
5. For the atrial beat, answer either (1) Why does it contribute only minimally
to ventricular filling? Or (2) What would keep the blood from flowing backward
into the veins coming into the atria?
1 blood goes from atria to ventricles even before the beat, 2 nothing except
those valves that are in veins
6. The first few moments of ventricular contraction fail to move blood into
the arteries. Why?
isovolumetric contraction is because semilunars remain closed until ventricular
pressure is higher than afterial pressure
7. You feel chest pain so you take nitroglycerine. How did this save you
from a heart attack?
relaxation of smooth muscle in coronary arteries would alleviate the block
(that likely resulted from a thrombus or an embolism in an artery already
partially occluded from atherosclerosis)
8. Why do the textbook artists color the pulmonary arteries blue?
they carry blood low in oxygen and high in carbon dioxide
9. Why can you hear the brachial artery below the blood pressure cuff when
the cuff pressure is between the systolic and diastolic levels?
Korotkoff sounds are when blood flow is turbulent from partly closed artery
10. In the atria, all that was needed to propagate the electrical signal
was the connections from one myocardial cell to the next. For the ventricles,
why was it important to have the added feature for propagation (bundle of
His and bundle branches)?
to start the contraction at the "apex" (bottom), to send the action
11. Three "leads" describe 3 different ways both wrists might
be fed in for measuring the ECG. Why might different people have differences
in how the ECG looks with the 3 leads?
orientation of heart (axis) can differ, abnormalities like murmurs might
create an asymetry in heart muscle
12. What would the sympathetic nervous system do to the shape of a myocardial
cell's action potential?
shorten that prolonged spike
13. A person drops over and has no pulse. To keep him or her alive until
medical equipment and personnel arrive, (answer either) (1) What is the
name of the procedure you would perform? Or (2) How would this keep the
CPR, it keeps the brain alive
14. "Re-entry of excitation:" After recovering from a heart attack,
why might some myocardial cells be excitable (no longer refractory), and
be triggered to fire, before the appropriate time (that appropriate time
being the time synchronized from the SA and AV nodes)?
a pathway of myocardial cells around the scar might be long
15. Why was a reminder of the process of receptor-mediated endocytosis by
clathrin-coated pits relevant in the context of heart attacks?
LDL is removed by that process
16. Why is asbestos more of a problem for smokers?
their cilia are paralyzed and cannot remove asbestos by the mucus elevator
17. Pick one: (1) A drug that specifically affects beta-2 adrenergic receptors
(terbutaline), or (2) a drug that blocks leukotriene action (Singulair).
What is the specific action that would help in asthma?
1 open airways by mimicing adrenalin or the sympathetic nervous system,
2 decrease inflammation
18. The partial pressure for oxygen in the atmosphere is atmospheric pressure
times the fraction of the atmosphere that is oxygen. What are the major
reasons that the partial pressure for oxygen in the alveoli is much lower?
there are higher proportions of water vapor and carbon dioxide
19. You have a subject and a spirometer. What value, a portion of total
lung capacity, cannot be obtained?
20. Give either the approximate number or the value relative to atmospheric
pressure of the intraplural during inhalation.
book says 754 mm Hg, the point is that it is slightly less than lungs which
are slightly less than atmospheric
21. Why does a premature baby have trouble breathing?
type 2 alveolar cells mature late and without surfactant, water pressure
impedes alveolar opening
22. Where, other than the medulla oblongata, are chemoreceptors located
that feed by nerves to the respiratory control centers?
aortic and carotid bodies
23. Relative to curve where % oxygen saturation is plotted as a function
of partial pressure for oxygen for adult hemoglobin, how would you place
the curve for fetal hemoglobin?
fetal oxyhemoglobin dissociation curve is to the left of the adult
24. Why does chloride come out of red blood cells in the lungs?
so bicarbonate can come in for the generation of carbon dioxide to be exhaled
25. Why is it advantageous for some animals to use uric acid rather than
urea in their excretory systems?
less water is lost
26. "Upwelling of nutrients off the coast of Peru." Answer either
(1) What ocean current helps with this? Or (2) What is the climate abnormality
that disrupts current and upwelling?
Humboldt current, El Nino
27. Non-steroidal anti-inflammatory drugs (NSAIDS) inhibit the formation
of what mediator of inflammation?
28. Peritubular capillaries (the vasa recta) form part of the kidney's portal
system. Where is the other capillary bed?
29. A basement lamina separates two components of the glomerular sieve.
Name one of these two cellular components.
podocyte's foot processes and fenestrated capillary
30. Facilitated diffusion for glucose takes place on the basolateral surface
of a proximal tubule cell. For EITHER of the other two essential components
of glucose transport in this cell type, give BOTH the membrane transporter
PLUS the location of the membrane.
cotransport-apical, sodium pump-basolateral
31. What function does it serve to have salt but not water transport in
the ascending limb from the loop of Henle?
to increase the osmolarity of the interstitial fluid
32. Elimination of what hormone from your body would make you crave salt?
33. ACE=angiotensin converting enzyme: Answer EITHER (1) What hormone from
the kidney activates ACE? Or (2) For what disorder might you want to inhibit
34. What, if any, type of polymer would be broken into monomers if given
enough time in the presence of salivary amylase?
35. Chief cells: answer EITHER (1) What is the name of the zymogen (precursor)
in the granules of these cells. (2) Acid secreted (from what cell?) helps
to form the active enzyme from the precursor?
36. A SEVERE stomach disorder was once attributed to excess stomach acid.
A further elucidation of this disorder was worthy of the 2005 Nobel prize
in medicine (awarded to Marshall and Warren). Answer either (1) What disorder?
Or (2) What was the cause of the disorder they discovered?
ulcer, bacterium (Helicobacter pylori)
37. Enzyme activity as a function of pH: describe the graphs for pepsin
vs. salivary amylase.
peaks are at 2 and 7 respectively
38. Say something about how or where trypsin is activated.
trypsin is activated in the intestinal lumen by chopping a fragment from
the zymogen under the influence of enderokinase on the brush border (or
by trypsin that has already been activated)
39. In reference to lipase in the intestinal lumen, tell me either (1) What
is the source of lipase? Or (2) What are the products when it acts on a
pancreas, monoglyceride plus two fatty acids
40. Why is the function of the hepatic portal vein so important?
It delivers materials absorbed from the intestines to the liver for detoxification
41. Amino acids stimulate G cells to release gastrin. State one of the secretions
that result from this.
One cell (ECL cell) puts out histamine causing parietal cell to put out
42. Using the correct terminology about the drug's affect on appetite (hunger),
tell me about amphetamine.
it is anorexogenid (it causes anorexia)
43. In its effects in the mammary gland and uterus, what kind of cell is
affected by oxytocin?
44. If a body builder abuses growth hormone, what is likely to happen to
his or her bones?
they will grow in thickness
45. What is a general term that takes into account the trophic influence
for both males and females of FSH, LH, ICSH and HCG?
46. What happens if there is too little thyroid hormone during an infant's
brain development is compromised (cretinism)
47. "The follicle includes a 'rind' of cells and the egg enclosed in
this rind." What does this rind do?
48. "There is a surge of LH." Answer one (1) Where did this LH
come from? (2) What kind of molecule is that LH? Or (3) Name one of the
effects that has on the ovary.
pituitary, peptide, convert flooicle to corpus luteum, cause ovulation
49. Would the endometrium build up and break down in women who are taking
the pill? (Include in your answer why or why not.)
yes, steroids would cause build up and duds (without steroids) would allow
50. What happens to the corpus luteum after implantation?
It is maintained and continues to secrete progesterone under the influence
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