HBY 531
MEDICAL PHYSIOLOGY
2003
Section 1: Answer the following using:
A = increase
B = remain the same
C = decrease
1.
During
the gastric phase of acid secretion, distension of the stomach will cause
plasma levels of gastrin to ________.
2.
CCK
concentrations in the blood will ________ with the introduction of H+
into the duodenum.
3.
Chief
cell secretion of pepsinogen will________ as CCK levels increase in the blood.
4.
The
concentration of chylomicra within plasma will ________ during the absorptive
state.
5.
Segmentation
and peristalsis within the small intestine will ________ in the presence of
substance P.
6.
In an
individual with Hirshbrung’s disease, the luminal diameter of the colon within
the region lacking Auerbach’s plexuses will ________ when compared to the
luminal diameter of the colon of an otherwise healthy individual.
7. Urinary Ca2+ excretion will ___________ following a sudden reduction in dietary phosphate.
8. Urinary PO43- excretion will ___________ following a sudden reduction in dietary phosphate.
9. For an individual that experiences hypoparathyroidism due to Mg2+ depletion, plasma Ca2+ levels will ___________ following a sudden reduction in dietary Ca2+.
10. The fractional absorption (i.e., the percent absorbed) of dietary Ca2+ will ___________ following a sudden reduction in dietary Ca2+.
11. The fractional absorption (i.e., the percent absorbed) of dietary Ca2+ will ___________ following the development of an adenoma of the parathyroid gland.
12.
The filtered load of Ca2+ within the kidneys
will ___________ following the development of an adenoma of the parathyroid
gland.
13.
During the growth of a secondary follicle (during the
latter portion of the follicular phase), FSH secretion by the pituitary will ________.
14.
After degeneration of the corpus luteum in the absence of pregnancy, plasma levels
of progesterone will ________.
15.
After degeneration of the corpus luteum during pregnancy, plasma levels
of progesterone will ________.
16. With the advent of menopause, bone resorption will ________.
17. Transcription of the b-subunit of LH will _________ following exposure of gonadotropes to an increase in testosterone.
18. Transcription of the b-subunit of LH will ________ following an increase in plasma prolactin.
19. Testosterone production by Leydig cells will ________ following an increase in estradiol levels within the interstitial fluids of the testis.
20. Intracellular concentrations of dihydrotestosterone (DHT) within cells of the prostate will _________ in response to a 5a-reductase inhibitor.
Section 2: For each of the following,
choose the single best response.
21. Achalasia:
a. is the result of an incompetent cardio-esophageal
sphincter (CES).
b. is the result of a chronically constricted
CES.
c. results in adenocaricinoma of the squamous
epithelium of the esophagus.
d. Both a and c are correct.
22. Lactose intolerance:
a. is the result of inflammatory diarrhea.
b. results in secretory diarrhea.
c. arises from the lack of the fructose
transporter.
d. None of the above is correct
23. A lack of enterokinase:
a. could cause diarrhea.
b. would affect the conversion of pepsinogen
into pepsin.
c. would decrease lipase activation.
d. would not affect the conversion of
trypsinogen to trypsin.
24. Intracellular elevation of cAMP:
a. promotes acid secretion in parietal cells.
b. alters the activity of chloride channels in
crypt cells.
c. does not affect chylomicra formation
d. all of the above are correct.
25. Elevation of intracellular Na+ in
a columnar absorptive cell of the small intestine:
a. will not affect monosaccharide uptake.
b. will affect fructose uptake.
c. will not affect dipeptide uptake.
d. None of the above is correct.
26. Gastrin levels:
a. will decrease as plasma somatostatin
concentrations are elevated.
b. are not affected by VIP.
c. are unaffected by H+ levels in the
stomach.
d. cause a decrease in the diameter of the
sphincter of Oddi.
27. The gastroileal reflex:
a. is triggered during the cephalic phase of
acid secretion.
b. Is triggered during the gastric phase of acid
secretion.
c. Is a short reflex
d. Both a and c are correct.
28. Hypersecretion of acid by parietal cells can
occur as a result of:
a. blockade of gastrin receptors.
b. lowered prostaglandin levels.
c. cutting the vagus nerve.
d. distension of the duodenum.
29. Chloride ion flux from crypt cells:
a. will be outward if the resting potential is
less negative than the chloride equilibrium potential.
b. will be inward if the resting potential is
more negative than the chloride equilibrium potential.
c. is modulated by PKA activity.
d. determines the resting potential of the crypt
cell.
30. Salivary gland secretion:
a. is always hyposmotic relative to plasma.
b. produces a constant Cl-
concentration regardless of flow rate.
c. Rate produces ~0.5L/day.
d. Is always hyperosmotic relative to plasma.
31. Damage to the 12th cranial nerve:
a. will affect the oral phase of swallowing.
b. can result in dysphagia.
c. will not affect the esophageal phase of
swallowing.
d. all of the above are correct.
32. During receptive relaxation,
a. stomach motility is reduced or lacking.
b. acid secretion by parietal cells is mediated
by factors such as gastrin and wall distension.
c. chief cell secretion of pepsinogen is
ongoing.
d. All of the above are correct
33. A female patient was admitted with frequent
morning spells of dizziness, complaining of fatigue and nausea. Fasting blood
glucose was found to be lower than normal, but a glucose tolerance test was
otherwise normal. The patient could be diagnosed with Addison’s disease if:
a. she had low levels of circulating cortisol,
and high levels of circulating ACTH.
b. there was hyperpigmentation of her skin due
to excess cortisol secretion.
c. a CAT scan of her adrenal gland showed
bilateral hypertrophy.
d. glycosuria was abnormally high because of
high ACTH levels.
34. Non-shivering thermogenesis is how human
newborns and certain rodents increase their body temperature when exposed to
cold, and is characterized by:
a. a-adrenergic stimulation of muscle contraction
b. b-adrenergic stimulation of brown adipose
tissue
c. decreased glycolytic rates and O2
consumption
d. the T3-dependent suppression of Na+/K+
ATPase transcription
35. The processing of insulin in the pancreatic
islet b-cell:
a. is stimulated by sympathetic nerve activation
to the pancreas.
b. is completed only after glucose or amino acid
dependent accumulation of ATP.
c. starts with the action of signal peptidase
and ends with the excision of the C-peptide.
d. is stimulated by glucose but not by amino
acids.
36. The glucose sensitivity of the endocrine
pancreas is determined by a combination of:
a. the high affinity glucose transporter
(GLUT-2) and the low Km enzyme Glucokinase.
b. the low affinity glucose transporter (GLUT-2)
and the ATP-sensitive Ca2+-channel.
c. the low affinity glucose transporter (GLUT-2)
and the high Km enzyme Glucokinase.
d. an inhibition of the voltage-sensitive Ca2+-channel
and the Kreb’s cycle.
37. A teen-aged patient has an enlarged thyroid
gland (Goiter). How would the following tests distinguish between Grave’s disease
and Hashimoto’s thyroiditis?
a. increased levels of TSH in Grave’s but not in Hashimoto’s.
b. the presence of TSH receptor stimulating immunoglobulins in
Grave’s.
c. higher levels of circulating T4 levels in Hashimoto’s.
d. increased levels of T4 and TSH in Grave’s,
but only T4 in Hashimoto’s.
38. Thyroid and steroid hormones:
a. both bind to intracellular receptors, but
only steroid hormones affect transcription rates.
b. both bind to intracellular receptors, but
only steroids displace heat shock proteins.
c. both depend on essential dietary precursors
for proper biosynthesis in their respective glands.
d. both increase progressively during waking
hours and are lowest during deep sleep.
39. Gonadotropin releasing hormone (GnRH) and follicle
stimulating hormone (FSH):
a. both act by binding to intracellular
receptors in gonadal cells.
b. both bind to G-protein coupled receptors with
7 transmembrane domains.
c. both stimulate degranulation of hormones in
their target tissues.
d. oppose each other’s action in regulating
estrogen release from the ovary
40. The biosynthesis of ACTH takes place in the
corticotrophs of the anterior pituitary:
a. in response to episodic secretion of
hypothalamic corticotropin releasing hormone.
b. as a large precursor, that also encodes luteinizing
hormone (LH) and b-endorphin.
c. and its secretion controls the synthesis of
adrenal cortisol, but not of adrenal androgens.
d. and in ectopic adrenal tumors, resulting in
hyperpigmentation.
41. The human adult relies predominantly on sweat
to cool the body because:
a.
cholinergic
stimulation results in increased production of a hypotonic protein-free
solution
b.adrenergic stimulation can increase rates of
sweat formation 50 fold to more than 2 liters / hour
c. apocrine gland blood supply is very sensitive
to small changes in acetylcholine levels
d.sweat gland blood flow is independent of
hypothalamic control.
42. Growth hormone and insulin are considered
anabolic hormones because they both:
a.promote glucose uptake and utilization.
b.activate intracellular tyrosine kinases and
promote amino acid uptake.
c.stimulate insulin-like growth factor (IGF)
synthesis in liver and their secretion.
d.promote fatty acid uptake and triglyceride
synthesis.
43. The catecholamine hormones epinephrine and nor-epinephrine act on liver
as follows:
a. epinephrine binds to an a-adrenergic membrane receptor, while
nor-epinephrine binds to an
intracellular b-adrenergic
receptor.
b. epinephrine activates glycogen synthesis
while nor-epinephrine increases glycogen hydrolysis.
c. nor-epinephrine decreases cAMP levels while
epinephrine decreases intracellular Ca2+ levels.
d. each binds to a unique G-protein coupled
receptor, but both stimulate gluconeogenesis.
44. The amino acid tyrosine is the precursor of
several hormones including:
a. cortisol, thyroxine (T4) and catecholamines.
b. thyroid releasing hormone (TRH), thyroxine
(T4) and cortisol.
c. glucagon, insulin and cortisol.
d. thyroxine (T4), epinephrine and dopamine
45. The post-absorptive state of metabolism, following a 12 hr fast, is
characterized by:
a. the induction of liver glucokinase and the
dephosphorylation of pyruvate dehydrogenase.
b. the phosphorylation and activation of adipose
triglyceride lipase and increased blood ketones.
c. a decrease in muscle protein catabolism and
in urine urea levels.
d. an increase in hepatic Fru-2,6-P2
levels and gluconeogenesis from Acetyl CoA.
46. A 2-year old child in an early morning hypoglycemic (low blood glucose)
coma is immediately given glucagon intravenously. After 10 min blood glucose
levels have still not returned to normal. Possible explanations are:
a. The patient has inherited a constitutively
active mutant of adenylate cyclase.
b. The patient has eaten only protein for
several days before the coma.
c. The patient has inherited a defective insulin
receptor gene.
d. The patient has inherited a defective
glucose-6-phosphatase gene.
47. The synthesis and
secretion of glucagon from
pancreatic islet a-cells in response to
amino acids from the diet:
a. Is simultaneous with insulin release, only
when blood glucose is high.
b. Is stimulated by insulin secretion from the b cells, when blood glucose is high
c. Decreases the level of urea in urine, because
of decreased de-amination by the liver
d. Increases gluconeogenesis, even in the
absorptive phase.
48. An obese Non-Insulin Dependent Diabetic (NIDDM) has decreased rates of
blood glucose clearance most probably because:
a. of increased insulin receptor substrate
(IRS-1) phosphorylation associated with obesity.
b. the expression of insulin processing
proteases (PC2 and PC3) decreases with age and obesity.
c. there is a down-regulation of insulin
receptors associated with increased body weight.
d. hepatic levels of fructose-2,6-bisphosphate
increase with age and obesity.
49. An orally administered synthetic compound
that mimics the structure of Fructose-2,6-bisphosphate (Fru-2,6-P2),
and is quantitatively removed from portal circulation by the liver would be
expected to:
a.
decrease
glycolytic rates by inhibiting phosphofructo-1-kinase.
b.decrease gluconeogenic rates by decreasing
PEPCK activity.
c.
decrease
gluconeogenic rates by inhibition of Fructose-1,6-bisphosphatase.
d.decrease glycolytic rates by inducing
glucose-6-phosphatase.
50. An untreated Insulin-Dependent Diabetic (IDDM):
a. would test positive for Islet-cell Antibody
(ICA) early during the progression of diabetes.
b. would show increased levels of lipoprotein
lipase expression in adipose endothelia.
c. would have decreased levels of circulating
fatty acids and ketones in the blood.
d. can be treated by daily administrations of
oral hypoglycemic agents and by exercise.
51. A 1 year old infant was brought in by his
parents, who described symptoms of weight loss, frequent urination and general
malaise that seem to follow shortly after weaning, and switching to less
frequent larger meals. Subsequent blood
analysis revealed a near normal fasting blood glucose level of 100 mg/dL, but
an abnormal glucose tolerance curve (blood glucose >300 mg/dL after 2 hr).
Radioimmunoassay of insulin revealed that the patient had a normal, to slightly
elevated, insulin response to the glucose load. Which of the following is NOT a likely explanation?
a. the patient has a mutated insulin gene that
decreases its binding affinity to the receptor.
b. the patient has a mutated insulin receptor
with decreased insulin binding affinity.
c. the patient has a pituitary adenoma that
secretes high levels of growth hormone.
d. the patient has a mutated glucose transporter
GLUT-2 with a lower Km for glucose.
52. If the patient in question #51 was found to
have a high blood C-peptide to insulin ratio during the glucose
tolerance curve, it could be concluded that:
a. the
mutation is in the sequence of the insulin molecule, and affects insulin
processing.
b. the
mutation of his insulin receptor caused a decrease in insulin binding and
clearance.
c. the
defect is subsequent to the binding of insulin to the receptor, i.e.
post-receptor.
d. the
mutation is in either of the insulin converting proteases, PC2 or PC3.
53. In a patient correctly diagnosed as having hypoparathyroidism, all of the following lab values would be expected to be low EXCEPT:
a. PTH
b. calcitriol
c. Ca2+
d. PO43-
e. both b and d
54. In a patient correctly diagnosed as having pseudohypoparathyroidism, all of the following lab values would be expected to be low EXCEPT:
a. PTH
b. calcitriol
c. Ca2+
d. PO43-
e. both a and d
55. A net loss of skeletal mass would be expected in all of the following conditions EXCEPT:
a. hyperparathyroidism
b. pseudohypoparathyroidism
c. type I vitamin D dependent osteomalacia
d. type II vitamin D dependent osteomalacia
e. both c and d
56. A patient that suffers from vitamin D resistant osteomalacia would benefit from which of the following?
a. dietary Mg2+ supplementation
b. dietary Ca2+ supplementation
c. dietary PO43- supplementation
d. intravenous injections of PTH
e. both b and d
57. Which of the following conditions is considered as secondary hyperparathyroidism?
a. vitamin D dependent osteomalacia
b. vitamin d resistant osteomalacia
c. vitamin D intoxication
d. hypercalcemia of malignancy
e. all of the above
58. All of the following conditions involve hypercalcemia EXCEPT:
a. primary hyperparathyroidism
b. vitamin D intoxication
c. vitamin D resistant osteomalacia
d. vitamin D dependent osteomalacia
e. both c and d.
59. Administration
of GnRH in a non-pulsatile manner would cause:
a. suppression of gonadal steroid secretion.
b. a high non-pulsatile release of gonadotropins.
c. no effect on either pituitary or
gonadal secretion.
d. upregulation of GnRH receptors in
the pituitary gonadotropin-secreting cells.
e. Both b and d.
60. The
LH surge:
a. is essential for ovulation.
b. occurs at the end of the luteal
phase.
c. is caused by the estrogen positive
feedback on the pituitary.
d. is
caused by the estrogen positive feedback on the pituitary and on the hypothalamus.
e. a and d.
61. The
corpus luteum:
a. produces progesterone but no estrogens,
under the influence of LH.
b. produces progesterone and estrogens, under the influence of LH.
c. produces only estrogens, under the
influence of FSH.
d. has a life span of 4 days.
e. none of the above.
62. During
the first week after implantation of the blastocyst in the uterus:
a. Nutrition is provided to the embryo
by the decidual cells.
b. Nutrition is provided to the embryo
by the trophoblast cells.
c. The placenta is able to sustain
pregnancy by secreting progesterone.
d. The corpus luteum is no longer
needed and finally degenerates.
e. a and b.
63. Milk
secretion:
a. is inhibited by estrogens and
progesterone.
b. requires the action of estrogens
and progesterone on the mammary gland.
c. requires a decrease in the hypothalamic
secretion of dopamine.
d. requires the action of prolactin.
e. all of the above.
64. What
is the best medical intervention in case of a placenta previa?
a. Administration of oxytocin to
induce parturition as soon as possible.
b. Treatment of the patient with
anti-hemorrhagic agents.
c. To perform a cesarean birth.
d. To prescribe bed rest and
anti-hypertensive agents.
e. None of the above.
65. The presence of antibodies within the lumen of the seminiferous tubules of the testis suggests a problem involving:
a. overproduction of androgen binding protein by Sertoli cells
b. overproduction of the protease inhibitor by peritubular myoid cells
c. tight junction formation between adjacent Sertoli cells
d. gap junction formation between Sertoli cells and primary spermatocytes
e. tonic contraction of peritubular myoid cells
66. With regard to the male sexual response, electrical stimulation of the pudendal nerve will be expected to stimulate:
a. secretion by the bulbourethral glands
b. contraction of the smooth muscle within the vas deferens
c. contraction of the smooth muscle within the seminal vesicles
d. contraction of the ischiocavernosus and bulbocarvernosus muscles
e. both b and c
67. With regard to the male sexual response, interruption of the lumbar splanchnic nerves will be expected to interfere with:
a. secretion by the bulbourethral glands
b. contraction of the smooth muscle within the vas deferens
c. contraction of the smooth muscle within the seminal vesicles
d. contraction of the ischiocavernosus and bulbocarvernosus muscles
e. both b and c
68. Which of the following conditions could account for male infertility involving oligospermia and decreased semen volume, but normal levels of LH, FSH, and testosterone?
a. hypogonadotropic hypogonadism
b. hypergonadotropic hypogonadism
c. cryptorchidism
d. blockage of one ejaculatory duct
e. androgen insensitivity
Section 3: Clinical
Scenario Questions. Choose the single
best response based on the following case studies:
Clinical Scenario 1: A patient complains of diarrhea,
which has been persistent for the last two weeks. He is not diabetic but does
drink heavily. He complains of developing a “beer gut” over the last 5 months
and swelling in his legs, which you determine is peripheral edema. His blood pressure is 80/60 and his pulse is
100 beats/minute. The patient also complains that he is very fatigued. He is
admitted to the hospital and subsequently his stool volume is revealed to be
2L/day based void volumes collected within the first 12 hours. Upon admission,
rehydration via intravenous feed was administered.
69. At this point, the most likely diagnosis is:
a. This patient is suffering from secretory
diarrhea.
b. Osmotic diarrhea is the cause.
c. Malabsorption is the cause.
d. It is impossible to unequivocally determine
which type of diarrhea the patient is suffering from.
70. Further tests reveal that the patient’s serum
electrolytes are normal with the exception of K+ (2.9 mM vs 4.0 mM).
Gastrin and VIP are normal. By day two,
the stool volume is 0.8L/day.
a. This patient is suffering from secretory
diarrhea.
b. Osmotic diarrhea is a better candidate than
secretory diarrhea based on the reduced stool volume.
c. This patient is suffering from irritable
bowel syndrome .
d. None of the above is applicable.
71. The blood tests also indicate that the
patient has compromised liver function and urine analysis shows elevated
aldosterone levels. Analysis of the
stool reveals no white cells and cultures are negative. The patient tells you
that he has recently (over the last month) started a new diet in which he
consumes large amounts of legumes. A mainstay of his diet is dried chick pea
which is rich in nutrients and minerals including magnesium (110 mg/100ml). He
has also began using an un-absorbable
artificial sweetener (sorbitol) in an attempt to reduce his “beer gut”.
a. The dietary change is the cause of the
secretory diarrhea.
b. Osmotic diarrhea is implicated because of the
magnesium intake.
c. Sorbitol is the source of the osmotic
diarrhea.
d. Both b and c are possible.
72. The lowered serum K+:
a. arises primarily as a consequence of the
diarrhea.
b. is a consequence aldosterone mediated K+
secretion.
c. is due to reduced acid secretion in the
stomach
d. is the cause of the rapid heart rate.
73. The “beer gut” and peripheral edema:
a. Are most likely due to the new diet.
b. are most likely due to compromised liver
function leading to fluid retention.
c. are coincidental with regard to the patient’s
conditions.
d. None of the above is relevant
Clinical Scenario 2: The
patient is a 48-year-old woman who sees her physician because her friends have
noted that she now appears to be “bent over,”, and she has noted increased back
pain and that she is now shorter than she had been.
Her
past medical history is significant because as a young adult she had been told
she was hypothyroid due to an auto-immune destruction of her thyroid gland. She
has been treated with one pill of thyroid hormone a day that she religiously
takes. When she was about 35, she noted pain in her joints associated with
objective inflammation and swelling of the affected joints. She was diagnosed
as having rheumatoid arthritis on the basis of her clinical picture and
diagnostic laboratory tests. Her flare-ups of the disease were treated with
anti-inflammatory agents (aspirin and ibuprophen), and for severe flare ups
prednisone in pharmacologic-dose would be added to her regimen for a brief
period of time. During the last 10 years of her rheumatoid arthritis, she has
been increasingly cavalier about her prednisone usage and now frequently doses
herself without physician monitoring for her joint discomfort. In the last 6
months because of a particularly prolonged bout of joint pain, swelling and inflammation,
she has treated herself with 20 mg/OD of prednisone (about four times the
normal physiologic amount of glucocorticoid that would be produced by a
normally functioning adrenal cortex). She has recently noted that she must get
up
After
six months of this self-directed prednisone therapy, and because of feeling
fatigued and weak, she saw her family physician. The physician noted that the
patient appeared to have a round and full face that appeared red and to exhibit
mild acne, have a fullness to her upper back and an enlargement to her
abdominal girth. She noted that small vessels were easily visible on her
abdominal waist and her upper leg muscles appeared wasted. Her reflexes were
normal.
Blood Work:
Patient
Serum Sodium 140mEq/L 135-145 mEq/L
Serum
potassium 3.5 mEq/L 3.5-5.0 mEq/L
glucose
fasting 170 mg/dL 70-110 mg/dL
Glucose 2 h
after meal 200 mg/dL less than 140 mg/dL
BUN and
creatinine normal
T4 7 mg/dL 5-12 mg/dL
TSH 3.0
mU/L 0.3-5.0 mU/L
74. The patient’s clinical presentation and laboratory data are consistent
with the diagnosis(es) of:
a. Hypothyroidism and acromegaly.
b. Hypothyroidism and Addison’s disease.
c. Cushing’s syndrome in a patient properly treated with thyroid hormone
(euthyroid).
d. Cushing’s syndrome and hyperthyroidism.
75. The patient’s clinical presentation and laboratory data are consistent
with which of the following statements:
a. Ketonemia and a high blood glucose are usually present in such a patient
as because the blood insulin level is usually very, very low in patients on
pharmacologic doses of glucocorticoids.
b. In this patient, while she treated her self with a high dose of
prednisone, her pancreatic islet b cells secreted an inadequate amount of
insulin to maintain her blood glucose levels within the normal range both
during fasting and after a meal.
c. The pharmacologic dose of prednisone taken by this patient decreased
the production of glucose (gluconeogenesis) by the liver and kidney.
d. The pharmacologic dose of prednisone taken by this patient acted as an
anabolic steroid increasing the size of her proximal muscles.
76. The pharmacologic dose of prednisone taken by the patient to treat her
symptomatic rheumatoid arthritis caused Cushing’s syndrome by:
a. lowering her insulin blood level and decreasing liver gluconeogenesis.
b. making her more insulin resistant, causing muscle to breakdown,
decreasing collagen synthesis, decreasing bone remodeling and producing osteoporosis.
c. increasing ACTH levels causing an increase in blood glucocorticoid
levels.
d. increasing CRH levels in the portal blood bathing the anterior
pituitary.
77. In this patient:
a. A low dose dexamethasone would suppress ACTH levels.
b. A high dose dexamethasone would increase ACTH levels.
c. Metyrapone administration would decrease glucocorticoid levels, and the
symptoms of Cushing’s syndrome would slowly abate.
d. ACTH levels would be low and TSH levels would
be normal.
78. Which of the following would be expected to take place after she
stopped taking prednisone?
a. Her frequent need to urinate at night would likely decrease.
b. Blood ACTH levels would likely greatly decrease.
c. Blood T4 levels would decrease back to her previous
hypothyroid state.
d. Liver production of glucose would greatly increase as her insulin
levels normalized.
79. The relief of her rheumatoid arthritis symptoms, albeit transitory, was
due to:
a. The anti-inflamatory affects of pharmacologic doses of corticosteroids.
b. The gluconeogenic affects of physiological doses of corticosteroids.
c. The diabetogenic affects of pharmacological doses of corticosteroids.
d. The increase in ACTH and endorphin levels produced by the pharmacological
doses of glucocorticoids.
80. The most likely diagnosis in this patient is:
a. Hypothyroidism with muscle wasting.
b. Pituitary adenoma producing an excessive amount of ACTH.
c. Rheumatoid arthritis with iatrogenically produced (i.e.,
physician-induced) Cushing’s syndrome.
d. Derangement in hypothalamic function producing elevated CRH levels.
Clinical Scenario
3: A 35 year old man presents to the emergency room following an accident
in which he fell down a flight of stairs while moving a refrigerator. The refrigerator fell across his thighs
partially crushing them in the process.
Following radiological evaluation, the injuries involve only soft tissues,
but the man develops symptoms of hypocalcemia.
Lab tests confirm the hypocalcemia, but plasma calcium levels returned
to normal over time. Assume normal
hormone function, and that dietary Ca2+ and GFR remained constant
over throughout the accident as well as during the compensatory phase.
81. During the time period in which plasma Ca2+ levels were restored to normal, which of the following processes were likely to have been increased in magnitude when compared to pre-injury magnitudes?
a. Ca2+ reabsorption within the kidney
b. Ca2+ absorption within the GI tract
c. Ca2+ efflux from bone as a result of bone resorption
d. both a and c
e. a, b, and c
82. During the compensatory phase, the patient would benefit from which of the following treatments?
a. intravenous calcitonin injections
b. dietary vitamin D (cholecalciferol) supplementation
c. dietary Mg2+ supplementation
d. dietary PO43- supplementation
e. none of the above
Clinical Scenario 4: A 26
year old man presents with symptoms involving painful muscle spasms and
occasional bone pain. A bone scan
reveals a moderate bone loss, and lab tests reveal moderate hypocalcemia but
pronounced hypophosphatemia.
83. Based on this information, the most likely cause of this patient’s hypocalcemia involves:
a. a dysfunction within the parathyroid glands
b. PTH receptor problem
c. a calcitonin-secreting tumor
d. a Mg2+ deficiency
e. none of the above
84. Follow-up tests done on this patient two weeks later reveal a further decrease in both plasma Ca2+ and PO43-, and that plasma calcifediol and calcitriol levels are also very low. Based on this information, the likely diagnosis of this patient is:
a. Pseudohypoparathyroidism
b. Vitamin D dependent osteomalacia due to a sunlight/dietary deficiency
c. Type I vitamin D dependent osteomalacia
d. Vitamin D independent osteomalacia
e. none of the above
Clinical Scenario 5: A
33 year-old patient seeks medical attention because her menstrual cycles have
disappeared. Lab tests show normal prolactin
levels, low gonadotropins and the absence of bleeding after a progesterone
withdrawal test.
85. Which of the following causes can
be ruled out without performing any additional tests?
a. pregnancy
b. a GnRH receptor disfunction
c. hypothalamic dysfunction
d. primary ovarian failure
e. none of the above.
86. What is the first test one
should perform?
a. Pregnancy
b. Measure TSH levels
c. Measure T4 levels
d. MRI of pelvic organs
e. Both b and c
Clinical Scenario 6: A
post-puberty girl presents with primary amenorrhea (never had a menstrual
period). Upon physical exam, she is
found to have normal breast development, but an underdeveloped clitoris and
labia minora, along with a blind vaginal pouch.
She also demonstrates sparse pubic and axillary hair. Ultrasound analysis confirms the absence of a
cervix and uterus, and the presence of testis-like masses within the inguinal
canal.
87. Based on this information, the most likely cause of this patient’s phenotype involves a defect with which of the following proteins?
a. 5a reductase
b. anti-mullerian hormone (AMH)
c. androgen receptors
d. testis-determining factor
e. both a and b
88. If a karyotype were done on this patient, it would likely reveal:
a. 46, XY
b. 46, XX
c. 47, XXY
d. 47, XXX
e. 45, XO
Clinical Scenario 7: A
male suspected of infertility is evaluated.
Semen analysis reveals oligospermia, but normal semen volume. Lab work reveals that plasma LH, FSH, and
testosterone levels are low, but GnRH levels are above normal, and demonstrate
a pulsatile secretion pattern with 10 bursts/day.
89. Based on this information, this individual’s infertility most likely is related to:
a. a prolactin-secreting tumor
b. a secretory defect within gonadotropes of the anterior pituitary
c. a secretory defect within Leydig cells of the testis
d. androgen insensitivity
e. either c or d
90. Infusion of human chorionic gonadotropin into this patient would most likely cause plasma testosterone levels to:
a. increase
b. remain unchanged
c. decrease