HBY 531 MEDICAL PHYSIOLOGY
Lecture Exam
3 Version 1
2002
Section 1: Answer the following using:
A = increase
B = remain the same
C = decrease
1. Pancreatic secretions will____A______as plasma levels of secretin increase.
2. The duration of the receptive relaxation reflex will_____C_____after partial or total vagotomy.
3. The gallbladder diameter will_____B_____in the presence of elevated levels of plasma gastrin.
4. Intestinal secretion arising from crypt cells will_____A_____upon exposure to VIP on their basolateral surfaces.
5. The H+ secretion rate of parietal cells____C______in response to secretin.
6. The absorption of amino acids will____C______in response to an increase in the intracellular Na+ levels in columnar absorptive cells.
7. During the absorptive state, the plasma LDL concentration will_____A_____.
8. Following transfusion of 1 L of blood containing citrate, urinary Ca2+ excretion will ______C_______.
9. Given a constant dietary input of calcium, the filtered load of Ca2+ will ___B or C______ in a patient started on furosemide treatment.
10. In a normal healthy individual in their mid 20’s, the fractional absorption of calcium along the GI tract will _______A______ following a change from a high calcium to a low calcium diet.
11. The rate of in vitro bone resorption, within a pure culture of osteoclasts, will _____B______ following infusion of PTH.
12. The rate of in vitro bone resorption, within a pure culture of osteoclasts, will ___A, B, or C_____ following infusion of a carbonic anhydrase inhibitor.
13. Within a normal healthy kidney, the transport maximum for phosphate will ____C____ following a change from a low phosphate to a high phosphate diet.
14. Following infusion of a membrane permeant analog of cAMP into the blood supply of the parathyroid gland, PTH levels within blood will _____A______.
15. In a patient with an ectopic ACTH-secreting tumor, gluconeogenesis within the liver will ___A, B, or C______ following treatment with metyrapone.
16. In a patient with an ectopic ACTH-secreting tumor, ACTH levels will _____B______ following a dexamethasone suppression test.
17. During the follicular phase, progesterone levels will____ A, B, or C ___.
18. During the follicular phase GnRH secretions will ___ A, B, or C ____.
19. The length of the endometrial glands ___A, B, or C____ during the follicular phase of the ovarian cycle.
20. Establishiment of a preovulatory follicle coinicides with a ____A, B, or C_____ in plasma levels of FSH.
21. The likelihood for monozygotic twins to form after the breakdown of the zona pellucida will ____A, B, or C_______.
22. Within the vascular sinuses of the corpora cavernosa of the penis, the hydrostatic pressure will ____C____ following stimulation of lumbar splanchnic nerves.
23. Within Leydig cells of the testis, the rate of conversion of cholesterol to pregnenolone will _____A______ following stimulation of LH receptors.
24. Within Sertoli cells of the testis, the rate of conversion of androgens to estrogens will _____A_______ following stimulation of FSH receptors.
25. Plasma FSH levels will be expected to ___C______ following an infusion of exogenous testosterone into an otherwise normal healthy man.
26. Sperm counts (e.g., number of spermatozoa/mL of semen) will be expected to ___C____ following an infusion of exogenous testosterone into an otherwise normal healthy man.
Section 2: For each of the following, choose the single best response:
27. In a crypt cell the intracellular Cl- is 20 mM and in the lumen it is 145 mM. Recall that ECl=25 ln (Clcell/Cllumen). The resting potential of the cell is -50 mV.
a. ECl is -30 mV.
b. activation of Cl- channels would result in an efflux of Cl- cytoplasm to lumen.
c. a and b are true.
d.
the net flux of Cl-
is near O.
28. Lactose intolerance:
a. will result in secretory diarrhea if large amounts of diary products are consumed.
b. occurs in persons who have had a vagotomy.
c.
occurs when there is
insufficient lactase enzyme functioning on the columnar absorptive cell.
d. is a result of insufficient numbers of glucose/Na+ as transporters.
29. The columnar absorptive cells of the ileum:
a.
contain Na+/bile
salt transporters.
b. contain no Cl-/HCO3- exchangers.
c.
contain no glucose/Na+ transporters.
d. b and c are true.
30. Which of the following is a feature of the gastroileal reflex? (note: version 3 extra answer was also correct)
a. relaxation of the muscularis externa of the ileum
b. it occurs during fasting only
c.
relaxation of the
ileocolonic sphincter by gastrin and VIP
d. it is triggered by distension of the colon
31. Plasma LDL enters tissues via:
a. transcytosis from capillaries.
b. is acted on by endothelial lipoprotein lipase (LPL) to become an HDL.
c. endocytosis into hepatocytes.
d.
both a and c are true.
32. Inhibition of the enzyme enterokinase would result in:
a. no change in carboxypeptidase A activity.
b. an increase in phospholipase A activity.
c.
the inhibition of
pancreatic amylase.
d.
none of the above.
33. Bile salts:
a. are recycled.
b. are resorbed by co-transport.
c. are synthesized by hepatocytes.
d. are lost in the feces at a rate of approximately 5% or less per day.
e.
all of the above.
34. A deficiency of Apo B-48 will result in:
a. a decrease of VLDL plasma levels during the absorptive state.
b. an increase in chylomicrons remnants during the absorptive state.
c. an elevated chylomicron concentration during the absorptive state.
d.
reduced chylomicron
formation.
Answer questions 35-37 using the information provided in the graph below:
An individual has ingested 1.0L of fluid with a pH of 6.7 at the 1 hour mark. You are monitoring stomach pH, stomach volume and small intestine volume.
35. The lack of changes in small intestine volume between hours 4 and 5 is most likely due to:
a. increased bile secretion.
b. the gastrocolonic reflex.
c. defecation.
d.
due to a balance between
intestinal secretion and solute absorption/resorption.
36. At the 3 hour make the sum total of secretions from the small intestine liver and pancreas is:
a. 3L.
b. 1L.
c. 2.5L.
d.
0L.
e. none of the above.
37. The number of mole of H+ produced at the 2 hour mark is:
a. 2 x 10-6 moles.
b. 7 x 10-5 moles.
c. 1 x 10-4 moles.
d. 2.5 x 10 -7 moles.
e.
none of the above.
38. The slow decline in small intestine volume between hours 0 and 2 is due to:
a.
solute
absorption/resorption.
b. the gastrocolonic reflex.
c. a lack of Cl- secretion in the small intestine.
d. the absence of the gastroileal reflex.
39. A patient suffers from a lack of pancreatic and bile secretions:
a. resulting in diarrhea.
b. caused by insufficient release of secretin and/or CCK into the duodenum.
c. caused by excessive secretin release of gastrin into the blood.
d.
a and b are true.
40. Chylomicra are found in lacteals of the gastrointestinal tract mucosa and not capillaries:
a. because the capillaries are sinisoids.
b.
because the chylomicra
are too large to enter the capillaries but not lacteals.
c. because lacteal form a intimate network of vessels adhere to the basement membrane underlying the columnar absorptive cells.
d. during the post-absorption state.
41. Administration of Aminoglutethimide
(an inhibitor of cholesterol P450 side-chain cleavage enzyme, P450scc) to a
patient would be expected to
a.
decrease cortisol levels in plasma.
b.
increase
estradiol levels in a plasma.
c.
decrease
anterior pituitary secretion of ACTH.
d.
increase
adrenocortical pregnenolone concentration.
42.
The
biosynthesis of tetra-iodothyronine (Thyroxine, T4)
a.
takes
place at the basal membrane of the thyroid follicular cell, catalyzed by a Na+/K+
ATPase.
b.
requires
the presence of circulating iodide transported by thyroglobulin in the blood.
c.
is catalyzed by thyroperoxidase at the apical membrane of the
follicular epithelium.
d.
is
inhibited in Graves’ disease due to the autoimmune inhibition of the Thyroid
Stimulating Hormone (TSH) receptor.
43.
The
secretion of Prolactin from the anterior pituitary is stimulated by suckling
because of;
a.
negative
feedback by dopamine to the anterior pituitary
b.
decreased
synthesis and secretion of oxytocin from the posterior pituitary
c.
decreased
secretion of Luteinizing and Follicle-stimulating hormones (LH & FSH) from
the anterior pituitary
d.
decreased secretion of dopamine from the hypothalamus
44.
Growth
hormone releasing hormone (GHRH) and somatostatin oppose each others action by
a.
stimulating and inhibiting, respectively, adenylyl cyclase activity
in the anterior pituitary.
b.
the GHRH
dependent stimulation of PLCb activity
and somatostatin dependent activation of adenylyl cyclase
c.
decreasing
and increasing, respectively, circulating IGF-1 levels
d.
competing
for a common receptor on anterior pituitary somatotroph plasma membranes.
45.
The
biosynthesis of ACTH takes place in the corticotrophs of the anterior
pituitary,
a.
where it
is derived from a large precursor that also encodes Luteinizing hormone and b-endorphin.
b.
and is
stimulated by hypothalamic Corticotropic Releasing Hormone (CRH) Gai-coupled inhibition of adenylyl cyclase.
c.
in response to episodic stimulation from the hypothalamus, with
maxima observed in late sleep and early morning.
d.
and its
secretion controls adrenal cortisol secretion but not adrenal androgens.
46. A patient has undergone a radical
bi-adrenalectomy (removal of both adrenal glands), and his physician asked for
a blood sample after a 12 hr fast. Which
of the following would be expected:
a.
levels
of cortisol in the blood would be expected to be normal
b.
levels of glucose in the blood would be expected to be below normal
c.
levels
of ACTH in the blood would be expected to be below normal
d.
levels
of aldosterone would be expected to be above normal
47. Non-shivering thermogenesis is the major
mechanism by which the newborn raises its body temperature;
a.
during
this process O2 consumption does not change appreciably.
b.
subcutaneous
temperature increases in parallel with O2 consumption.
c.
the catabolism of fats in brown adipose tissue is increased.
d.
independent
of b-receptor activation of brown adipose tissue
temperature.
48. A resting volunteer had a respiratory
quotient of 0.8 and an O2 consumption of 300 ml/min, with an energy
equivalent of 4.81 kcal / liter O2, the metabolic rate under these
conditions would be expected to be:
a.
2080 kcal/day
b.
4160
kcal/day
c.
2.08
cal/hr
d.
4.16
cal/hr
49. Growth hormone and insulin share similar
mechanisms of action including
a.
binding
to heterotrimeric G-protein coupled plasma membrane receptors that result in
the activation of tyrosine kinase.
b.
the
activation of liver adenylyl cyclase and the stimulation of glycogen synthesis.
c.
the activation of intracellular tyrosine kinases following the
interaction of agonist with a homodimeric receptor.
d.
the
stimulation, in liver, of insulin-like growth factor (IGF) synthesis and
secretion.
50. The continued administration of dexamethasone
to a stressed-out medical student would be expected to
a.
decrease
ACTH secretion from the anterior pituitary but not Corticotropin Releasing
hormone (CRH) from the hypothalamus.
b.
result
in the atrophy of normal adrenal tissue because of excessive CRH and ACTH
secretion.
c.
increase
a-melanocyte stimulating hormone (a-MSH) and b-endorphin
in the adrenocorticotrophs of the anterior pituitary.
d.
decrease both CRH and ACTH secretions, resulting in bilateral
adrenal atrophy
51.
The catecholamine hormones epinephrine and nor-epinephrine act on liver
as follows:
a.
epinephrine
binds to an a-adrenergic
plasma membrane receptor, while nor-epinephrine binds to an intracellular b-adrenergic receptor
b.
each binds to a different kind of plasma membrane receptor, but both
cause increases in liver gluconeogenesis.
c.
nor-epinephrine
decreases intracellular cAMP levels, and epinephrine decreases intracellular Ca2+
levels
d.
epinephrine
activates glycogen synthesis while nor-epinephrine activates VLDL synthesis.
52.
The amino acid tyrosine is the precursor of several hormones including
a.
cortisol,
thyroid hormones T3/T4 and catecholamines.
b.
thyroid hormones T3/T4, epinephrine and nor-epinephrine.
c.
glucagon,
insulin and cortisol.
d.
insulin,
thyroid hormones T3/T4 and cortisol.
53.
The absorptive state of metabolism, following the ingestion of a
balanced meal is characterized
by:
a.
the induction of liver glucokinase and the dephosphorylation of
pyruvate dehydrogenase.
b.
the
phosphorylation and activation of adipose triglyceride lipase acids in the
blood and increased ketone synthesis.
c.
a
translocation of GLUT-2 to liver plasma membrane, resulting in an increase in
glucose uptake.
d.
an
increase in blood free fatty acid levels and increased ketone biosynthesis.
54.
Excess
secretion of growth hormone in post-pubertal patients can be considered an
acute metabolic disorder because
a.
fatty acid uptake as well as triglyceride synthesis in adipose
tissue are dramatically increased.
b.&n