HBY 531 Organ Systems
Final Examination
1998
Section 1: Answer the following using:
A = increase, or an increase
B = remain the same, or no change
C = decrease, or a decrease
1. Secretin concentration in the blood will ________ with the entry of H+ into the duodenum.
2. The gastrocolonic reflex is characterized by__________ in motility in the ileum.
3. In the absence of sympathetic and parasympathetic activity to the GI tract, receptive relaxation will _________.
4. In general, the transmitter VIP will cause _________ in smooth muscle contraction.
5. Chief cell secretion of pepsinogen will _________ if automonic input is reduced
6. During the absorptive state the synthesis and secretion of bile salts arising from hepatocytes will ________ .
7. Inhibition of the enzyme that carries out 11b-hydroxylation in the eventual synthesis of cortisol will result in ____________ in the rate of ACTH secretion by the anterior pituitary.
8. Treatment with dexamethasone will result in ____________ in ACTH and cortisol levels in the blood.
9. Inhibition of the deiodinase II enzyme (hypothalamus and anterior pituitary) will result in ___________ in circulating levels of T4.
10. The growth of the zona fasciculata and reticularis will __________ with a deficiency of 11b-hydroxylase.
11. Protein phosphorylation of pyruvate kinase will result in __________ in its activity.
12. Protein phosphorylation of glucokinase will result in __________ in its activity.
13. Protein phosphorylation of 6-phosphofructo-2-kinase will result in _________ in its activity.
14. PTH input to the proximal tubule cells results in ___________ in the rate of Na+/PO43- cotransport across the apical membrane.
15. As extracellular fluid volume decreases, Ca2+ reabsorption in the proximal tubule will __________.
16. Activation of Ca2+ activated Ca2+ channels in the plasma membranes of osteoclasts results in ___________ in enzyme release from the cell.
17. Chemical analysis of bone mineral shows that as one moves from the mineral front to regions deep within bone matrix, the molar ratio of calcium/phosphorus will __________.
18. As circulating levels of epinephrine increase following stimulation of the adrenal medulla, the rate of mucus production by the urethral glands of the penis will __________.
19. As plasma testosterone levels increase in a post-pubertal male, the circulating pool of biologically active androgens will __________.
20. Stimulation of adrenergic receptors on GnRH-neurons of the hypothalamus results in __________ in GnRH secretion.
21. Inhibin will result in __________ in androgen production by theca cells.
22. Progesterone will result in _________ in body temperature.
23. LH will result in ___________ in proliferation of luteal cells.
24. Human chorionic somatotropin (hCS) will result in __________ in maternal insulin sensitivity.
25. Progesterone will result in __________ in maternal immune responsiveness during pregnancy.
26. Estriol will result in ___________ in progesterone binding protein levels.
27. Estriol will result in ___________ in placental uptake of low density lipoproteins.
Section 2: For each of the following, choose the single best response.
28. During the absorptive state:
a. VLDL levels in the blood are solely dependent on their synthesis by columnar absorptive cells.
b. VLDLs lose triglycerides via the action of endothelial lipase.
c. no glycogen is stored in the liver.
d. the majority of absorbed lipids pass through the liver before the heart.
29. With regard to diarrhea:
a. osmotic diarrhea arises when a solute is present in the intestinal lumen which can not be absorbed.
b. enterotoxins such as Cholera Toxin cause osmotic diarrhea.
c. disaccharidease deficiencies can result in secretory diarrhea.
d. Cl- channel gene defects of pancreatic cells can result in secretory diarrhea.
30. With regard to bile:
a. bile usually contains no bilirubin.
b. bile salts are resorbed in the colon.
c. the majority of bile salts are resorbed in the jejunum and ileum.
d. bile salts are synthesized largely by the action of intestinal bacteria.
31. During the gastric phase of acid secretion:
a. stomach motility is enhanced by elevated plasma gastrin.
b. pepsinogen is most active in the stomach.
c. GIP (glucose insulinotropic peptide) secreted into the blood will increase the contractile frequency of the stomach and stimulate exocrine pancreatic secretions.
d. distension of the stomach is ineffective in stimulating H+ secretion.
32. Lactose intolerance:
a. can result in an osmotic diarrhea when milk is ingested.
b. is due to a lack of the enzyme sucrase normally found on the apical surface of absorptive cells of the small intestine.
c. is a result of a lack of both the fructose transporter and the enyzme sucrase which are normally found on the apical surface of absorptive cells of the small intestine.
d. is an example of secretory diarrhea.
For questions 33-37 refer to data in figure above. Resting or empty stomach volume is 100 mL. The secretions from the salivary glands amounted to 100 mL. Stomach volume graphed is total minus the empty volume. Small intestine volume is the total volume within the duodenum, jejunum and ileum. The individual ingested a meal consisting of 100 grams of solids and 1100 mL of fluid. The fluid had a pH of 7.0 and was isosmotic relative to plasma. The arrow indicates the start of the meal. The individual ingested the meal within 15 minutes. The individual had not ingested any food-stuffs for at least 16 hours prior.
33. The small intestine volume between hours 1 and 2:
a. is reduced because of CCK induced absorption of bile salts.
b. declines as a result of the gastroileal reflex.
c. is reduced because of the action of the hormone secretin on postganglionic parasympathetic neurons in the myentric plexuses of the jejunum.
d. is reduced due to the action of the pyloric sphincter.
34. The total volume secreted by the stomach between the 1 hour and 2 hour marks is:
a. 1.2 L
b. 2.5 L
c. 0.5 L
d. 3.0 L
e. none of the above.
35. The decline in small intestine volume after hour 4:
a. represents the beginning of solute absorption only.
b. represents the beginning of net solute absorption only.
c. is due to the volume being moved into the large intestine.
d. represents net solute and water absorption and resorption.
e. none of the above is correct.
36. The total volume secreted by the small intestine, pancreas, and liver by hour 4 is closest to:
a. 4.0 L
b. 3.5 L
c. 2.0 L
d. 1.0 L
e. 0.5 L
37. The data in the figure:
a. illustrate no reflex actions within the stomach and small intestine.
b. illustrate a reflex described as receptive relaxation.
c. indicates the individual must be suffering from dumping syndrome.
d. indicates the individual is lacking Cl-/HCO3- exchangers on small intestine columnar absorptive cells.
38. With regard to motility, which of the following statements is FALSE?
a. Segmentation rates in the ileum are 8/minute.
b. Perstalitic waves occur in the stomach at a frequency of 3/minute.
c. Nitric oxide causes increases in the segmentation rate in the duodenum.
d. The muscularis externa in the sigmoid colon remains cronically contracted if the neurons of the myentric and submucosal plexuses are absent.
39. With regard to the salivary glands, which of the following statements is FALSE?
a. They deliver approximately 1500 mL of fluid to the oral cavity per day.
b. They contain duct cells which have K+ and Cl- channels on their basal surfaces.
c. Under fasting conditions they deliver a hypotonic solution to the oral cavity which is the result of solute exchangers of Cl-/HCO3-, Na+/H+ and H+/K+ transporters on the apical surface, low water permeability and the action of lumenal carbonic anhydrase.
d. They do not respond to the adrenergic stimulation.
40. The slow wave:
a. is a low amplitude action potential which propagates at a velocity of 50 cm/sec.
b. will always give rise to a contraction of smooth muscle cells within the muscularis externa.
c. rising phase is thought to arise from a Ca2+ influx and/or inactivation of the Na+,K+-ATPase.
d. plateau is equal to the K+ equilibrium potential.
41. The exocrine secretions of the pancreas:
a. are all secreted in an inactive form.
b. contain some enzymes which are secreted in an active form and other which are secreted in an inactive form.
c. are stimulated by the hormone GIP.
d. are inhibited by the hormone gastrin.
42. In the epidermis:
a. there is only one cell type.
b. the permeability barrier is embodied in the tight junctions between keratinocytes of the stratum spinosum.
c. the turn over time for a keratinocyte is ~14-28 days.
d. large amounts of collagen are found.
43. An individual sweats at a rate of 1200 mL for 2 hours and is working in the shade. The ambient temperature is 85° F. There is no breeze and the individual is wearing a shirt and pants. The metabolic rate of the individual during this three hour period is 400 Kcal/hour Assume the metabolic rate is proportional to/equivalent to total heat lost per hour in Kcal/hour. Also assume radiative heat loss is insignificant.
a. The individual's body core temperature would drop under these conditions.
b. The majority of the heat loss is via heat conduction.
c. The amount of heat lost due to heat conduction is 724 Kcal/hour.
d. The amount of heat lost due to heat conduction is 76 Kcal/hour.
44. Hormone binding to plasma proteins serves several purposes and has significant consequences. Among these are:
a. it decreases the circulating half time (t1/2) of the hormone.
b. it provides a "reservoir" of hormone and as such can serve to "buffer" acute changes in hormone secretion.
c. protein-bound hormone more easily passes through cell membranes and therefore is more easily excreted in the urine.
d. it makes it usually unnecessary to measure "free" hormone levels in the blood.
45. Specificity of hormone action is determined by:
a. the chemical nature (peptide, protein, amino acid, steroid, or ion) of the hormone, which targets its action to affect metabolism, differentiation, or cell division.
b. the transit time of the hormone from the site of production to its target cells.
c. the presence of high affinity hormone receptors on target cells.
d. the t1/2 of the hormone in circulation.
46. Which of the following hormones acts by binding to a specific intracellular receptor?
a. Thyroid stimulating hormone (TSH)
b. Adrenocorticotropic stimulating hormone (ACTH)
c. Prolactin
d. Epinephrine
e. Aldosterone
47. Factors known to increase ACTH secretion include all EXCEPT:
a. stress and anxiety.
b. corticotropin releasing hormone (CRH).
c. antidiuretic hormone (ADH).
d. rapidly drinking 16 ounces of regular Coca Cola producing a transient but significant hyperglycemia.
e. no caloric intake for 24 hours but access to water as desired.
48. The FALSE statement about POMC is:
a. It is a prohormone for melanocyte stimulating hormone (MSH).
b. Its synthesis is regulated by CRH.
c. It is made in the anterior pituitary and the hypothalamus.
d. POMC is synthesized from ACTH.
49. Cortisol has the following effect(s):
a. It decreases the synthesis of glucose by the liver.
b. In pharmacologic doses, it increases muscle mass and strength by sparing muscle catabolism.
c. It increases the secretion rate of CRH.
d. It has a direct positive feedback effect on ACTH secretion.
e. In a pharmacologic dose, it is strongly anti-inflammatory.
50. T3:
a. increases the sensitivity of the thyrotrophs of the anterior pituitary to TRH so that TSH levels rise.
b. selectively decreases the expression of the TRH gene.
c. increases the secretion of TSH.
d. inhibits prolactin gene expression.
51. Which of the following is NOT an effect of human Growth Hormone?
a. It decreases the production of somatomedins.
b. It increases lipolysis in fat cells (adipocytes).
c. It decreases insulin-dependent glucose uptake in muscle cells.
d. It increases the growth of organs such as liver and kidney.
52. A patient with an ACTH-secreting pulmonary bronchogenic carcinoma (ectopic production of ACTH) would most likely present with:
a. a large adrenal adenoma with signs and symptoms of Cushing’s Syndrome.
b. bilateral adrenal hyperplasia with signs and symptoms of Cushing’s Syndrome.
c. increased blood aldosterone levels with low blood pressure.
d. low blood sugar, low blood pressure and an increase in fat about the trunk.
53. In the thyroid gland, iodide is oxidized into an active intermediate by thyroid peroxidase (TPO). Another function of TPO is:
a. proteolysis of thyroglobulin to produce thyroid hormone (T4).
b. removal of iodide form MIT and DIT for resynthesis of thyroid hormone.
c. transport of iodide from the extracellular space into the thyroid follicular cell.
d. the iodination of tyrosine residues of thyroglobulin by "active-iodide" and the "coupling" reaction to form precursor T4 and T3.
54. In Addison’s disease (destruction of the adrenal cortex, usually by an autoimmune process) you would expect the patient to have:
a. a decrease in the blood level of ACTH.
b. significant hyperglycemia.
c. a decrease in both blood sugar and blood pressure.
d. none of the above.
55. In a patient being treated daily with a pharmacologic-dose of Dexamethasone (a potent glucocorticoid) you would expect:
a. the ACTH and cortisol blood levels to be markedly decreased.
b. the patient to suffer from hypoglycemia and to be very insulin sensitive.
c. the patient to show loss of appetite.
d. the patient to show resistance to infection.
56. If a person with NORMAL thyroid function is treated with T3, which of the following changes will become apparent within 48 hours?
a. Blood T4 levels will decrease.
b. Thyroglobulin synthesis by follicular cells will increase.
c. Iodide uptake by the thyroid will markedly increase.
d. TSH levels will significantly increase.
e. Cortisol levels will increase.
57. While IRS is the Internal Revenue Service, IRS-1 is:
a. the phosphorylated insulin receptor.
b. an intracellular protein with multiple serine/threonine phosphorylation sites.
c. a tyrosine kinase phosphorylation substrate and site for SH-2 binding proteins.
d. a tyrosine kinase.
58. Insulin stimulates glucose transport into muscle cells by:
a. increasing the rate of transport of each individual GLUT4 transporter.
b. increasing the affinity of the transporter for glucose (decreasing the Km).
c. decreasing glucose transporter mRNA.
d. stimulating transporter recruitment to the plasma membrane.
59. Simultaneous increases in cylic AMP in pancreatic islet beta cells and in liver cells rarely happens because:
a. the first results in increased insulin secretion, while the second is a result of an increase in glucagon secretion.
b. the first results in increased insulin gene transcription, while the second results from decreased glucagon gene transcription.
c. the first is inhibited by glucagon, while the second is stimulated by glucagon.
d. glucose must be low for the first to happen, but high for the second.
60. Amino acids in the blood stimulate both glucagon and insulin release from pancreatic islet cells:
a. only if the ratio of blood glucose to fatty acid is low.
b. to allow for liver gluconeogenesis even in the absorptive phase.
c. to increase VLDL synthesis in liver.
d. to prevent hepatic urea synthesis.
61. Lipoprotein lipase is stimulated:
a. when insulin levels are high.
b. when apoprotein B2 is present on the surface of chylomicrons.
c. when glucagon levels are high.
d. when apoproteins E and B2 are present on HDL particles.
62. The insulin gene:
a. is expressed both in pancreatic islet beta cells and in intestinal GIP secreting cells.
b. is only expressed when glucose is present.
c. codes for a single polypeptide chain that is cleaved into four peptides.
d. is absent in pancreatic islet beta cells of Type II diabetics.
63. An injection of an antibody to insulin into the portal vein would:
a. decrease glucagon secretion from islet cells, only if glucose levels are low.
b. increase glucagon secretion from islet cells regardless of glucose levels.
c. increase liver glycogen synthesis.
d. decrease liver gluconeogenesis.
64. An untreated Type I diabetic (IDDM) will:
a. have high C-peptide to insulin ratios in his blood.
b. have increased adipose triglyceride lipase activity.
c. have decreased urine output because of low insulin levels.
d. have high levels of glucokinase mRNA in their liver because of increased blood glucagon.
65. A patient was told to fast before a glucose tolerance test, after 8 hours of fasting the patient lost consiousness and was found to have very low blood glucose levels. Which of the following is/are plausible explanations for this condition?
a. The patient has a mutated form of glucagon.
b. The patient has an overexpression of glucose-6-phosphatase in their liver.
c. The patient has a pancreatic islet alpha cell tumor that produced too much glucagon.
d. The patient has an increase in the phosphorylation of liver glycogen synthase kinase-3.
66. Which of the following conditions involves the simultaneous elevation of plasma Ca2+ and PO43- above normal?
a. type I vitamin D dependent osteomalacia
b. vitamin D resistant osteomalacia
c. primary hyperparathyroidism
d. secondary hyperparathyroidism associated with renal failure
e. none of the above
67. Which of the following conditions involves an elevation of plasma calcitriol?
a. type I vitamin D dependent osteomalacia
b. vitamin D resistant osteomalacia
c. secondary hyperparathyroidism associated with renal failure
d. hypoparathyroidism
e. none of the above
68. Following the inadvertent removal of all 4 parathyroid glands, which of the following set of conditions are expected?
a. hypocalcemia, hypophosphatemia, and elevated calcitriol
b. hypocalcemia, hypophosphatemia, and low calcitriol
c. hypocalcemia, hyperphosphatemia, and low calcitriol
d. hypocalcemia, hyperphosphatemia, and elevated calcitriol
e. hypercalcemia, hypophosphatemia, and elevated calcitriol
69. Following the removal of an adenoma of the parathyroid gland in a patient with primary hyperparathyroidism, which of the following will occur (relative to the condition before surgery)?
a. The plasma Ca2+ concentration at which PTH secretion is half-maximal will increase.
b. The plasma calcitriol levels will increase.
c. The rate of bone resorption will increase.
d. The plasma phosphate levels will increase.
e. All of the above will occur.
70. During a period of a prolonged dietary deficiency of phosphate, which of the following will occur?
a. 1a -hydroxylase activity will increase.
b. Intracellular concentrations of cAMP within chief cells will increase.
c. Ca2+ reabsorption in the distal tubule will increase.
d. Urinary phosphate excretion will increase.
e. None of the above will occur.
71. Which of the following cell types DOES NOT possess intracellular vitamin D receptors?
a. chief cells of the parathyroid gland
b. columnar absorptive cells of the small intestine
c. osteoblasts
d. osteoclasts
e. both a and d
72. Which of the following relationships concerning calcium homeostasis occurs during the postnatal growth phase?
a. Net GI absorption equals urinary excretion, and the rates of bone deposition and resorption are equal.
b. Net GI absorption exceeds urinary excretion, and the rates of bone deposition and resorption are equal.
c. Net GI absorption exceeds urinary excretion, and the rate of bone deposition exceeds bone resorption.
d. Net GI absorption is less than urinary excretion, and the rate of bone resorption exceeds bone deposition.
e. Net GI absorption is less than urinary excretion, and the rate of bone depostion exceeds bone resorption.
73. Concerning Ca2+ reabsorption within the nephron, which of the following statements is FALSE?
a. The majority of calcium is reabsorbed in the proximal tubule.
b. PTH stimulated increases in Ca2+ reabsorption involve both the transcellular and paracellular pathways.
c. The majority of Ca2+ reabsorption in the proximal tubule is via the paracellular pathway.
d. As free ionic Ca2+ in plasma increases above normal, urinary excretion also increases.
74. Inhibition of chief cell PTH secretion is dependent on:
a. a Ca2+ influx from extracellular fluids.
b. an activation of adenylyl cyclase.
c. elevated levels of intracellular Mg2+.
d. an increase in the rate of Ca2+ extrusion from the cell via the Ca2+-ATPase and the Na+/Ca2+ exchanger.
e. an increase in IP3 formation.
75. Which of the following enzymes is correlated (both spatially and temporally) with active mineralization?
a. tartrate-resistant acid phosphatase
b. alkaline phosphatase
c. collagenase
d. peroxidase
e. none of the above
76. Which of the following events will lead to the cessation of osteoclastic bone resorption?
a. A decrease in the pH of the resorption compartment.
b. Activation of transforming growth factor (TGF) b .
c. An increase in the Ca2+ concentration within the resorption compartment.
d. Activation of PTH receptors.
e. All of the above.
Questions 77-79 pertain to three different male patients who report that they and their respective wives have failed to conceive following a whole year of regular sexual intercourse without contraception. Suspecting that these men may in fact be infertile, you order lab tests involving a semen analysis and blood tests following 72 hours of abstinence. Answer the following.
77. Lab tests for patient 1 indicate that his sperm count is low (oligospermia), and blood tests reveal that his testosterone, LH and FSH levels are all low relative to normal. At this point, you discover that upon stimulation with human chorionic gonadotropin, his LH and FSH levels remain unchanged. Based on this information, which of the following could explain this patient's infertility? (A, B, C, D, or E: should have read GnRH stimulation test!)
a. Defective androgen synthesis.
b. An androgen insensitivity (i.e., androgen receptor problem).
c. A pituitary tumor involving unregulated secretion of prolactin.
d. A defect within gonadotrophs involving the transcription of the b subunit.
e. None of the above
78. Lab tests for patient 2 indicate oligospermia, normal LH and testosterone, but elevated FSH. The most likely cause of this condition involves:
a. lack of feedback inhibition at the level of the hypothalamus.
b. lack of feedback inhibition at the level of the pituitary.
c. hypersecretion of GnRH by hypothalamic neurons.
d. elevated estradiol levels.
e. none of the above.
79. Blood tests for patient 3 indicate normal LH, FSH, and testosterone. Semen analysis reveals an elevated sperm count, a pH of 7.5, but a volume of only 0.75 ml. Which of the following could be the cause of this man's infertility?
a. Blockage of both vas deferens.
b. Retrograde ejaculation.
c. Congenital absence of the prostate gland.
d. Congenital absence of both seminal vesicles.
e. Both a and d.
80. In the normal genetic and phenotypic male, the product of the SRY gene is a protein called testis determining factor (TDF) which does all of the following EXCEPT:
a. initiates processes that result in inactivation of the X chromosome.
b. inhibits expression of the gene for aromatase.
c. enhances the expression of the gene for anti-Mullerian hormone (AMH).
d. initiates processes that direct the cells of the coelomic epithelium of the indifferent gonad to differentiate into Sertoli cells.
81. An individual that has 46,XY has a congenital absence of the gene for 5a -reductase. Which of the following would be expected?
a. The Mullerian ducts will differentiate into their adult derivatives.
b. The genital tubercle will differentiate into a clitoris.
c. The genital swellings will fuse to form a scrotum.
d. Fetal LH levels will be elevated relative to normal.
82. Interruption of the lumbar splanchnic nerves on both sides will affect:
a. nitric oxide release in the penis.
b. contraction of the ischiocavernosus muscle.
c. contraction of the smooth muscle in the vas deferens.
d. secretion of the bulbourethral glands.
83. Sertoli cell production of inhibin will:
a. feedback on pituitary gonadotrophs to decrease LH production.
b. decrease the contractile activity of peritubular myoid cells.
c. decrease the number of tight junctions between adjacent Sertoli cells.
d. stimulate Leydig cells to increase testosterone production.
84. Androgen binding protein:
a. levels are regulated only by circulating levels of androgens.
b. secretion increases in response to FSH.
c. is synthesized in both the liver and testis.
d. stimulates gonadotrophs to increase FSH secretion.
85. In men, LH release by gonadotrophs:
a. is directly stimulated by activin.
b. will fall to low levels in the absence of circulating testosterone.
c. is stimulated by dopamine.
d. is pulsatile with 8-10 bursts/day.
86. Severe menstrual bleeding:
a. is associated with all anovulatory cycles.
b. is more frequent in obese women.
c. is observed with endometriosis.
d. is observed in women taking estrogen.
e. b, c and d are correct.
87. Which of the following are NOT effects of FSH?
a. increased cellular division of granulosa cells
b. increased number of FSH receptors on granulosa cells
c. increased aromatase synthesis
d. increased number of LH receptors on granulosa cells
e. increased number of LH receptors on theca cells
88. LH surge:
a. reflects the action of high estrogen levels on estrogen primed hypothalamus and pituitary.
b. is associated with a small surge in FSH.
c. is preceded by a small surge in GnRH.
d. stimulates production of hyaluronic acid in the follicle, which contributes to separating the oocyte from the granulosa layer.
e. all of the above are correct.
89. A 25-year-old woman has recent (4-6 weeks) secondary amenorrhea. Evaluation should include measurements of:
a. height/weight ratio, HCS, LH, FSH, estrogen.
b. height/weight ratio, human chorionic gonadotropin, prolactin, FSH.
c. FSH, testosterone, progesterone, estrogen, prolactin.
d. GnRH, height/weight ratio, prolactin, thyroid function, FSH.
90. The developing fetus produces which of the following?
a. Estradiol
b. Cortisol
c. 16-OH-DHEA
d. Estriol
e. Progesterone