HBY 531 Organ Systems
Final Examination 1995
Section 1: Answer the following using:
A = increases
B = no change, or remains unchanged
C = decreases
1. The diameter of the lumen of the pyloric-duodenal junction (pyloric sphincter) ____________ when blood plasma levels of secretin are elevated.
2. The diameter of the lumen of the junction between the ileum and the large intestine (ileocolonic sphincter) ___________ when blood plasm levels of secretin are elevated.
3. The diameter of the lumen of the junction between the ileum and the large intestine (ileocolonic sphincter) ___________ when blood plasm levels of gastrin are elevated.
4. Immediately anterior to a region of distension within the small intestine the electrical activity and contractile activity __________.
5. Immediately posterior to a region of distension within the small intestine the electrical activity and contractile activity __________.
6. Slow wave activity and action potential frequency in the small intestine ___________ with increased parasympathetic input to Auerbach's plexuses.
7. CCK (cholesystokinin) causes ____________ in the bile dependent secretions of the liver.
8. An increase in the secretion rate of the exocrine portion of the pancreas results in __________ in the total osmolarity of the secretion.
9. Inhibition of enterokinase will result in __________ in the enzymatic activity of pepsinogen.
10. The Na+ absorption in the ileum __________ with a reduction of H+ within the cytoplasm of columnar absorptive cells.
11. Inhibition of the Na+/K+ pump in columnar absorptive cells will result in ___________ in amino acid absorption.
12. Glucose insulinotrophic peptide will result in _________ in acinar secretions in the exocrine pancreas.
13. H+ transport into the lumen of the stomach __________ with an inhibition of the HCO3-Cl secondary transporter on the basal surface of parietal cells.
14. The number of HDLs derived from chylomicrons __________ with an inhibition of endothelial lipoprotein lipase (lipase on the apical surface of endothelial cells).
15. As hepatic VLDL production is increased, the plasma LDL concentration __________.
16. If the CETP activity is increased, HDL size __________.
17. If apo CIII concentrations are decreased, the plasma VLDL concentration __________.
18. If dietary fat content increases, intestinal fat absorbtion __________.
19. Following the release of cortisol from the adrenal cortex, protein catabolism __________.
20. Decreased phosphate reabsorption in the renal tubules would lead to __________ in the plasma Ca2+ concentration.
21. The plasma TSH level in an infant __________ upon exposure to cold.
22. Activation of LH receptors on Leydig cells leads to __________ in the activity of adenylate cyclase.
23. Dopamine input to gonadotrophs will result in __________ in FSH secretion.
24. Androgens produce __________ in the relative amount of biologically active circulating testosterone.
25. Increased testosterone input to peritubular myoid cells will cause __________ in the secretion rate of hSCSP-80.
26. Increased activin input to Leydig cells results in __________ in the secretion rate of testosterone.
27. The speed of conduction of the ventricular action potential __________ when gap junction number is doubled.
28. The pressure gradient for blood flow between the arterial and capillary segments of the circulation __________ as arteriolar resistance decreases.
29. Inflation of the lungs reflexively __________ peripheral vascular resistance.
30. Compared to control values, fibrosis __________ residual volume.
31. Intravenous infusion of HCl will lead to __________ in renal production of NH3 from glutamine.
32. An increase in tubular fluid flow in the thick ascending limb will lead to __________ in renin secretion.
Section 2: For each of the following statements, choose A if the statement is true, or B if the statement is false.
33. Thyroid hormone exerts its actions at the level of gene expression.
34. The most biologically active form of throid hormone is T4.
35. The synthesis of pregnenolone from cholesterol requires hydroxysteroid dehydrogenase.
36. Administration of estrogen can induce an LH surge in postmenopausal women.
37. Estrogens increase placental progesterone synthesis by increasing uptake of low density lipoproteins.
38. Penetration of the zona pellucida of the ovum by the first sperm induces an alteration in zona surface glycoproteins.
39. Inhibition of peritubular myoid cell secretion will increase the permeability of the blood-testis barrier.
40. Wolffian duct cells express 5-alpha-reductase activity prior to differentiation.
41. An individual (karyotype = 46,XY) that has a congenital absence of the gene that codes for androgen receptors will develope a testis, but will have female internal and external genitalia.
42. An individual with a congenital absence of the gene that codes for dynein will be infertile.
43. A shortening of the QRS complex is indicative of an increase in the conduction in the AV node.
44. Increasing the pressure of the blood in the carotid sinus will lengthen diastasis.
45. If the preload on a patient's heart has increased, her stroke volume will also increase.
Section 3: For each of the following, choose the single best response.
46. In the lymphatic system:
a. the spleen is one of the major sites of antibody production in humans.
b. lymph nodes produce the major response to blood borne antigens.
c. the spleen has a capsule of reticular connective tissue.
d. the thymus has a stroma of mesenchymal origin.
47. Lymphatic vessels:
a. are surrounded by a spiral wrapping of smooth muscle.
b. have many two way valves.
c. maintain lymph fluid at pressures equal to that of arterial blood.
d. are lined by reticular connective tissue cells.
48. In the thymus:
a. mature T cells migrate from medulla to cortex.
b. afferent lymphatics pass through the capsule into the cortex.
c. reticular epithelial cells form a sheath around the capillaries that contributes to the blood thymus barrier.
d. fibroblasts form the Hassall's corpuscles.
49. With regard to the thymus which is NOT true?
a. The thymus is most active in the third decade of life.
b. Greater than 80% of the T cells produced in the thymus are destroyed before ever leaving the thymus.
c. Lobules are incompletely separated by connective tissue septa.
d. The organ is composed of two lobes.
50. With respect to T cells which is NOT true?
a. They recognize foreign antigens only when associated with self MHC.
b. They are generally long lived in the body.
c. They undergo somatic mutation when they encounter a foreign antigen.
d. They are necessary for the production of most, but not all, antibodies.
51. With respect to the lymphocytes:
a. T cells make up over 60% of the lymphocytes in the body.
b. T cells do not divide after leaving the thymus.
c. B cells prefer to differentiate within dense irregular connective tissue.
d. T cells proliferate to form lymph nodules.
52. With regard to lymphocytes in a lymph node, which is NOT true?
a. Lymphocytes can enter the lymph node in the lymphatic fluid.
b. Lymphocytes can enter the lymph node by leaving the blood through post capillary venules.
c. T lymphocytes are found preferentially in the inner cortex.
d. Resting B cells fill the medullary sinuses.
53. In the lymphatic system:
a. lymphatic infiltrations have a capsule of dense irregular connective tissue.
b. lymphatic nodules appear as pairs.
c. germinal centers are centers of lymphatic nodules.
d lymph fluid is rich in platelets.
54. A hypothetical case: the maximal H+ concentration attended during the cephalic and gastric phases of acid secretion are about 100 mM . A patient presents with gastric secretion levels for H+ of 15 to 20 mM as measured during the cephalic phase. Intravenous injection of gastrin releasing peptide (GRP) caused H+ secretion to increase to the 80 mM mark.
a. There are no endocrine cells within the mucosa of the pyloric stomach which secrete gastrin.
b. There are no gastrin receptors on the baso-lateral surface of the parietal cells.
c. The endocrine cells of the stomach are hypersensitive to H+ in the stomach lumen.
d. Neurons within the submucosal and Auerbach's plexuses of the stomach that secrete GRP are absent or in reduced numbers.
e. a and b above are true.
55. Acid secretion by parietal cells:
a. would be enhanced if the Cl /Na exchanger on the basal surface was absent or inhibited.
b. would be inhibited if cholinergic receptors for acetylcholine were activited by ACh.
c. requires the presence of intracellular Ca2+ and ATP.
d. is inhibited by the activity of carbonic anhydrase.
56. Another hypothetical case: A patient presents complaining of diarrhea and shows signs of protein deficiency. Stool analyses reveal polypeptides derived from ingested foods. Under controlled conditions when the patient consumed foods containing only amino acids and no large proteins, the stools contained no amino acids from the ingested foods. Further, with continued adminstration of monomeric amino acid food stuffs the other symptoms stopped.
a. The columnar absorptive cells of the small intestines contain no dipeptide and tripeptide transporters.
b. Gastrin plasma levels are low.
c. Secretin secretions may be inadequate.
d. Pepsinogen secretion is reduced or absent.
e. c and d are true.
Use the graph for questions 57 and 58.
The graph above illustrates the inorganic components of saliva in relative amounts during fasting (minimal) and eating (maximal) for the normal individual and (A) a patient. The line labeled A represents the Na+ ion concentration measured in the patient. All other ion concentrations (Cl-, HCO3- and K+) were within 15% of their normal values throughout the flow rate range tested.
57. The patient's inability to regulate Na+ ion concentration might be due to:
a. poor Na+/K+ exchange by acinar cells.
b. poor Na+/K+ exchange by duct cells
c. leaky tight junctions between duct cells.
d. a reduction in the number of Na+/K+ ATPase pumps on the basal surface of duct cells.
e. b, c and d are all possible.
58. The osmolarity of the patient's saliva:
a. is always more hypotonic than plasma.
b. is always more hypertonic than plasma.
c. increases with increased flow rate far less than the normal case.
d. is unchanged relative to flow rate.
e. a and d are true.
59. Depletion of the enzyme lactase on the columnar absorptive cells of the small intestine will:
a. have no effect on galatose transport.
b. result in facilitated fructose transport.
c. cause reduced solvent absorption and result in diarrhea
d. result in the cessation of Na+ absorption in the small intestine.
e. result in decreased vitamin K absorption.
60. With regard to ion transport in the colon:
a. blockage of the HCO3-/Cl- exchanger(transporter) would not cause a decrease in Na+ absorption.
b. All Na+ absorption (resorption) occurs via a Na+/H+ exchanger (transporter).
c. Inhibition of the Na+/K+ ATPase pump would only influence Na+ resorption.
d. All transport is characterized by co-transport or exchange transport processes.
e. a thru d are incorrect.
61. X-ray of a patient reveals gallstones which are blocking the common bile duct. Which statement is false?
a. Examination of stools would most likely reveal fat within the stools.
b. During the absorptive state blood samples would reveal suppressed levels of chylomicrons in the blood.
c. Columnar absorptive cells would compensate by increasing their rate of endocytosis of lipid droplets from the intestinal lumen.
d. HDL levels might be expected to be lower than normal.
e. Fat soluble vitamin absorption would cease.
62. Vasoconstriction of 60% of the precapillary sphincters in the salivary glands would:
a. decrease the maximium attainable salivary flow rate.
b. have no effect on flow rate.
c. result in the saliva being hypertonic.
d. result in the saliva containing little or no amylase.
e. b and c are true.
63. The gastrocolic reflex:
a. is an example of a long reflex only.
b. requires distension of the stomach.
c. results in the movement of material from the ileum into the colon.
d. is activated by the presence of acid and hypertonic solutions in the duodenum.
e. b and c are true.
64. An infant presents with severe neurological problems and bleeding tendencies. Upon further examinination, you learn that plasma triglyceride levels are extrememly low even after a meal. You suspect a defect in:
a. bile acid production.
b. apo B-48 synthesis.
c. pancreatic enzyme production.
d. all of the above.
e. none of the above.
65. A patient deficient in LCAT would have:
a. small sherical HDL.
b. discoidal HDL.
c. no HDL.
d. normal HDL.
e. all of the above.
66. Which of the following pituitary hormones is an opioid peptide?
a. alpha melanocyte stimulating hormone
b. beta melanocyte stimulating hormone
c. ACTH
d. growth hormone
e. beta-endorphin
67. Which of the following hormones has the shortest half-life?
a. corticosterone
b. renin
c. dehydroepiandrosterone
d. aldosterone
e. norepinephrine
68. Calcitonin:
a. antagonizes the action of PTH.
b. is controlled by serum Ca2+ levels.
c. decreases osteoclastic function.
d. all of the above.
e. none of the above.
69. 1,25 dihydroxycholecalciferol affects intestinal Ca2+ absorption through a mechanism that:
a. is comparable to the action of adrenocortical hormones.
b. is comparable to the action of polypeptide hormones.
c. activates adenylate cyclase.
d. increases cell turnover.
e. changes gastric acid secretion.
70. Which of the following hormones exerts no effect on growth?
a. growth hormone
b. testosterone
c. T4
d. insulin
e. cortisol
71. Hypothalamic control of growth hormone secretion:
a. is only influenced by GHRH.
b. is under tonic inhibition by somatostatin.
c. is under dual regulation by GHRH and somatostatin.
d. is under negative feedback regulation by dopamine.
e. none of the above.
72. Which of the following is an example of negative feedback regulation?
a. angiotensin II regulation of aldosterone production
b. T3 regulation of TRH expression
c. CRF regulation of ACTH secretion.
d. all of the above
e. none of the above.
73. A 36 year old woman was referred to a university hospital for evaluation of spells of dizziness and weakness. These spells typically last for 10 min and are occurring with increasing frequency. The spells usually came after a large meal and could be terminated by her eating candy or drinking fruit juice. After each episode the patient was hungry and tired, and her memory was blurred. The patient's physical examination was within normal limits. Her blood glucose after an overnight fast was 2.1 mM (normal blood glucose is 5 mM), and 2.6 mM four hours after a glucose tolerance test. If the blood level of free fatty acids (FFA) is examined, it is expected to be:
a. lower than normal because of inhibition of fatty acid release from adipose tissue.
b. lower than normal because there is an increase in the rate of ketone body production.
c. normal.
d. higher than normal in order to compensate for the low level of glucose.
74. Hybridization of islets of Langerhans with DNA probes to insulin and glucagon mRNAs shows that:
a. all the cells express both insulin and glucagon.
b. only the beta cells express insulin and glucagon.
c. only insulin is expressed in the islets.
d. none of the above.
75. Isolated islets of Langerhans are incubated with high concentrations of either glucose or 2-deoxyglucose (a non-metabolized sugar) for one hour. Insulin release:
a. is enhanced for only 1-2 min, and ceases thereafter unless ATP is added to the medium.
b. gradually increases under both conditions.
c. is biphasic only in islets incubated in the presence of glucose.
d. none of the above.
76. The presursors of glucose synthesized during prolonged starvation are:
a. amino acids and fatty acids.
b. amino acids, lactate, glycerol, and fatty acids.
c. amino acids, lactate, and glycerol.
d. amino acids, lactate and fatty acids.
77. While the IRS is the Internal Revenue Service, IRS1 is:
a. a tyrosine kinase.
b. a serine/threonine kinase.
c. a protein with multiple tyrosine phosphorylation sites.
d. the insulin receptor in its phosphorylated form.
78. Activation of the insulin receptor involves:
a. autophosphorylation at multiple tyrosines in the beta subunit.
b. recruitment of other proteins to the beta subunit.
c. an increase in the level of cAMP in the cell.
d. direct interaction of the receptor with a subunit of a G protein.
79. Glucagon, but not insulin:
a. is a polypeptide.
b. is synthesized as a larger molecular mass precursor.
c. acts on hepatic cells.
d. none of the above.
80. Insulin stimulates glucose transport to muscle cells by:
a. increasing the affinity of the transporter to glucose.
b. increasing the Vmax of the reaction.
c. increasing both the affinity to glucose and the Vmax of the reaction.
d. none of the above.
81. Livers from fed or 72 hour starved rats were perfused with glucose-free isotonic medium containing glucagon and radioactive alanine (both at optimal concentrations). After four hours, both media were found to contain glucose. However, while the medium for the fed animal contained mostly non-radioactive glucose, the medium from the starved rat contained mostly radioactive glucose. The reason(s) for these results is(are):
a. the investigator mistakenly switched the label on the tubes. The opposite results are expected.
b. glucagon (acting via cAMP) induces glycogenolysis in the liver from the fed animal, and gluconeogenesis in the liver from the starved rat.
c. glucagon (acting via cAMP) induces glycogenolysis in the liver from the starved rat, and gluconeogenesis in the liver from the fed animal.
d. none of the above.
82. Glucose stimulates insulin release in isolated islets of Langerhans unless:
a. glucagon is present in the medium.
b. Na+ ions are present in the medium.
c. Ca2+ ions are not present in the medium.
d. all of the above are required.
83. Release of muscle amino acids during starvation is stimulated because:
a. protein degradation is stimulated in the absence of insulin.
b. protein synthesis is inhibited in the absence of insulin.
c. amino acid transport to muscle cells is inhibited in the absence of insulin.
d. all of the above.
84. The rate-limiting step that mediates glucose-control of insulin release is:
a. an ATP-sensitive K+ channel.
b. the enzyme glucokinase.
c. the beta-cells glucose transporter (GluT2).
d. a specific membrane-bound glucose receptor.
85. The molar concentration of insulin was found to be significantly higher than that of C-peptide. These findings suggest:
a. the blood was withdrawn shortly after a carbohydrate-rich meal.
b. the blood was withdrawn shortly after an insulin injection.
c. a tumor of the pancreas that over-expresses insulin.
d. over-expression of the converting enzymes (PC3 and PC2).
86. Changes in the endometrium that occur during the proliferative phase of the menstrual cycle include all of the following except:
a. proliferation of glandular cells.
b. leukocyte infiltration.
c. vascular growth.
d. stromal edema.
87. The hormone that is most likely responsible for stimulation of aromatase activity in granulosa cells is:
a. FSH.
b. LH.
c. GnRH.
d. estrogen.
e. progesterone.
88. The hormone that is most likely responsible for resumption of meiosis in the primary follicle is:
a. FSH.
b. LH.
c. GnRH.
d. estrogen.
e. progesterone.
89. A 30 year old patient with secondary amenorrhea and hyperprolactinemia is likely to have:
a. a hypothalamic disorder.
b. a disorder of the pituitary (e.g., adenoma).
c. an ovarian disorder (ovarian steroid defect).
d. a genetic defect in the uterus.
e. a breast disorder (response to chronic suckling).
90. Which of the following does not increase in pregnancy?
a. estradiol
b. prolactin
c. glucagon
d. aldosterone
e. cortisol