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__________as plasma levels of secretin increase.
2.
The duration of the
receptive relaxation reflex will__________after partial or total vagotomy.
3.
The gallbladder
diameter will_________in the presence of elevated levels of plasma gastrin.
4.
Intestinal secretion
arising from crypt cells will__________upon exposure to VIP on their
basolateral surfaces.
5.
The H+
secretion rate of parietal cells_________in response to secretin.
6.
The absorption of
amino acids will__________in response to an increase in the intracellular Na+
levels in columnar absorptive cells.
7.
During the absorptive
state, the plasma LDL concentration will__________.
8.
Following transfusion
of 1 L of blood containing citrate, urinary Ca2+ excretion will
_____________.
9.
Given a constant
dietary input of calcium, the filtered load of Ca2+ will __________
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 _____________
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 ___________
following infusion of PTH.
12. The rate of in
vitro bone resorption, within a pure culture of osteoclasts, will ________
following infusion of a carbonic anhydrase inhibitor.
13. Within a normal healthy kidney, the transport maximum for
phosphate will ________ 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 ___________.
15. In a patient with an ectopic ACTH-secreting tumor,
gluconeogenesis within the liver will _________ following treatment with
metyrapone.
16. In a patient with an ectopic ACTH-secreting tumor, ACTH
levels will ___________ following a dexamethasone suppression test.
17. During the follicular phase, progesterone levels
will_______.
18. During the follicular phase GnRH secretions will _______.
19. The length of the endometrial glands _______ during the
follicular phase of the ovarian cycle.
20. Establishiment of a preovulatory follicle coinicides with a
_________ in plasma levels of FSH.
21. The likelihood for monozygotic twins to form after the
breakdown of the zona pellucida will ___________.
22.
Within the vascular
sinuses of the corpora cavernosa of the penis, the hydrostatic pressure will
________ following stimulation of lumbar splanchnic nerves.
23. Within Leydig cells of the testis, the rate of conversion
of cholesterol to pregnenolone will ___________ following stimulation of LH receptors.
24. Within Sertoli cells of the testis, the rate of conversion
of androgens to estrogens will ____________ following stimulation of FSH
receptors.
25. Plasma FSH levels will be expected to _________ 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 _______ 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 0.
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?
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