Instructions: Unless otherwise specified, select the single best response.
1. Motor neurons in the myenteric plexus that stimulate the contraction of visceral smooth muscle in the gastrointestinal tract release:
A. acetylcholine
B. vasoactive intestinal polypeptide
C. nitric oxide
D. somatostatin
E. enkephalins
2. Postganglionic parasympathetic neurons innervating circular and longitudinal layers of gastrointestinal smooth muscle are located in:
A. myenteric plexus
B. submucosal plexus
C. paravertebral ganglia
D. prevertebral ganglia
3. The term “brain of the gut” is used to refer to the:
A. autonomic ganglia
B. enteric nervous system
C. migratory motor complex
D. interstitial cells of Cajal
4. Which of the following strategies would most likely be therapeutic in an individual with achalasia?
A. Injection of tetanus toxin into the lower esophageal sphincter
B. Surgical division of the lower esophageal sphincter
C. Administration of a muscarinic receptor agonist
D. Administration of a nitric oxide synthase inhibitor
5. Which of the following inhibits gastric acid secretion by an action on the parietal cell?
A. Acetylcholine
B. Epinephrine
C. Gastrin
D. Histamine
E. Prostaglandin E
6. Vagally mediated increase in gastric acid secretion is partly mediated by:
A. gastrin releasing peptide (GRP)
B. gastric inhibitory peptide (GIP)
C. vasoactive intestinal polypeptide (VIP)
D. somatostatin
7. The ‘postprandial alkaline tide’ is abolished by:
A. antrectomy
B. gastrin
C. parietal cell vagotomy
D. total inhibition of gastric H+-K+ ATPase
E. truncal vagotomy
8. The release of gastrin from G cells in the antrum of the stomach is inhibited by:
A. activation of vagal efferent fibers to the stomach
B. circulating epinephrine
C. blood-borne calcium
D. mechanical distention of the stomach
E. somatostatin
9. The basal acid output / maximum acid output ratio is normally closest to:
A. 0.1
B. 0.4
C. 0.7
D. 0.9
10. The optimum pH for the activity of pepsin is:
A. less than 1
B. between 1.6 and 3.2
C. between 3 and 5
D. between 6 and 7
11. From a physiologic standpoint, the advantage of a ‘parietal cell vagotomy’ over truncal vagotomy for treating duodenal ulcer is that in parietal cell vagotomy:
A. a gastrojejunostomy is not required
B. only basal acid output is reduced
C. G cells are also denervated
D. pyloric sphincter is also denervated
E. receptive relaxation is abolished
12. Which of the following hormone(s) is/are normally released by the stomach into the systemic circulation?
A. Ghrelin
B. Gastrin
C. Pepsinogen
D. Secretin
E. Vasoactive intestinal polypeptide
13. Gastric emptying is slowest after a meal containing:
A. fat
B. carbohydrate
C. protein
D. indigestible fiber
14. In which of the following segments in the splanchnic circulation is pressure least in a healthy individual at rest?
A. Hepatic arteriole
B. Hepatic sinusoid
C. Hepatic vein
D. Terminal branches of portal vein in the liver
E. Venule in the small intestinal mucosa
15. The least oxygenated and consequently the zone in the hepatic acinus most vulnerable to ischemia is:
A. zone I
B. zone II
C. zone III
16. Conjugation of bilirubin with glucuronic acid in the liver:
A. makes it hydrophobic
B. makes it hydrophilic
C. enables bilirubin to easily cross cell membranes
D. is always increased in neonatal jaundice
17. Normally, the rate-limiting step in the metabolism of bilirubin is:
A. uptake by ligandin
B. conjugation with glucuronic acid
C. secretion into bile
18. Which of the following is a bile acid synthesized by the hepatocyte?
A. Sodium taurocholate
B. Chenodeoxycholic acid
C. Deoxycholic acid
D. Lithocholic acid
19. Bile acids are synthesized starting from:
A. cholesterol
B. fatty acids
C. lecithin
D. bile salts
20. The most abundant bile acid is:
A. cholic acid
B. chenodeoxycholic acid
C. deoxycholic acid
D. lithocholic acid
21. Which of the following transporters is present only in the sinusoidal membrane of hepatocytes?
A. Bile Salt Export Pump
B. LDL-cholesterol receptors
C. MDR 3 (Flippase)
D. Multidrug Resistance associated Protein – 2 (MRP-2)
22. Bile salts are essential for absorption of fat because they:
A. solubilize dietary lipids in micelles
B. increase surface tension
C. are hydrophobic
D. contain pancreatic enzymes
23. Micelles in bile are formed by:
A. bile salts and phospholipids
B. bile acids and bile salts
C. cholesterol and bile salts
D. cholesterol and phospholipids
24. The total circulating bile salt pool is approximately:
A. 35 mg
B. 3.5 g
C. 150 mg
D. 30 g
25. The normal rate of bile salt synthesis is: A. 0.05 – 0.1 g/day
B. 0.2 – 0.4 g/day
C. 0.8 – 1.2 g/day
D. 2 – 2.5 g/day
26. Physiologically, the most important choleretic(s) is/ are:
A. bile salts
B. CCK
C. secretin
D. gastrin
27. Removal of the liver is fatal because:
A. blood urea rises
B. jaundice develops
C. clotting time is prolonged
D. progressive hypoglycemia occurs
28. Slow waves in the GIT are believed to be initiated by:
A. I cells
B. K cells
C. interstitial cells of Cajal
D. S cells
29. The most alkaline exocrine secretion is:
A. bile
B. pancreatic juice
C. intestinal juice
D. saliva
30. The term ‘hormone’ was coined by Ernest H. Starling to describe the actions of:
A. secretin
B. insulin
C. growth hormone
D. glucagon
31. Trypsinogen, a pancreatic proenzyme, is activated by:
A. enterokinase
B. hydrochloric acid
C. HCO3
D. pancreatic trypsin inhibitor
32. Most pancreatic zymogens are activated in the duodenal lumen by:
A. enterokinase (enteropeptidase)
B. trypsin
C. trypsin activator protein
33. Trypsin inhibitor:
A. inhibits the action of pancreatic enzymes in the lumen of the duodenum
B. inhibits activation of trypsin in the pancreas
C. deficiency is implicated in acute pancreatitis
D. is produced by enterocytes
34. Which of the following enzymes is not
synthesized by the pancreas?
A. DNAase
B. Proelastase
C. Aminopeptidases
D. Pepsin
35. Which of the following is an endopeptidase?
A. Carboxypeptidase A
B. Deoxyribonuclease
C. Trypsin
D. Dipeptidase
36. Which of the following enzymes is located in the brush border of enterocytes in the small intestine?
A. Lactase
B. Colipase
C. Cholesterol ester hydrolase
D. Lingual lipase
37. Disaccharidases are present in:
A. pancreatic acinar cells
B. brush border of enterocytes
C. D cells of pancreas
D. Brunner’s glands
38. Quantitatively, the most important enzyme in the digestion of fat is:
A. lingual lipase
B. gastric lipase
C. pancreatic lipase
D. lipoprotein lipase
39. Normally, instillation of acid into the duodenum to reduce pH in its lumen to 4 would most likely:
A. stimulate gastrin release
B. increase output of trypsin
C. increase secretion of Brunner’s glands
D. relax the pyloric sphincter
40. The major humoral mediator of meal- stimulated enzyme secretion is:
A. secretin
B. CCK
C. GIP
D. gastrin
41. The major humoral mediator of pancreatic duct cell secretion of bicarbonate rich juice is:
A. secretin
B. CCK
C. somatostatin
42. The major humoral mediator of gall bladder contraction in response to a fat meal is:
A. CCK
B. gastrin
C. secretin
D. somatostatin
43. Which is the most important cholagogue?
A. Secretin
B. CCK
C. Gastrin
D. GIP
44. The most potent stimulus for release of secretin from the duodenum is:
A. a reduction in duodenal lumen pH to < 4.5
B. peptides
C. fatty acids with > 8 carbons
D. carbohydrates
45. Which of the following statements about CCK is incorrect?
A. It causes gall bladder contraction.
B. It relaxes the sphincter of Oddi.
C. It relaxes the pyloric sphincter.
D. It stimulates the secretion of an enzyme-rich pancreatic juice.
46. Which of the following statements regarding somatostatin is incorrect?
A. It inhibits release of growth hormone.
B. It inhibits release of insulin.
C. It decreases blood flow to the intestine.
D. It stimulates gastric acid secretion.
47. In which of the following conditions is a long acting analog of somatostatin of therapeutic value?
A. Acute mesenteric ischemia
B. Bleeding from esophageal varices
C. Cholelithiasis
D. Pancreatic exocrine insufficiency
E. Pernicious anemia
48. In healthy humans, the maximal rate of glucose absorption from the intestine is estimated to be about:
A. 10 g/hour
B. 40 g/hour
C. 120 g/hour
D. 180 g/hour
49. Intestinal absorption of which of the following does not directly utilize a Na+ gradient?
A. Fructose
B. Galactose
C. Glucose
D. Phenylalanine
E. Tyrosine
50. Which of the following mechanisms allows complete absorption of glucose from the intestinal lumen into the cytosol of the enterocyte?
A. Simple diffusion through GLUT-5
B. Na-glucose cotransporter-1 (SGLT-1)
C. Na channels in enterocyte membrane
D. Paracellular uptake via gap junctions
51. Which of the following proteins is a regulator or iron absorption by enterocytes?
A. Ferritin
B. Hemosiderin
C. Hepcidin
D. Transferrin
52. The major protein that transports iron in the plasma from the site of absorption to cells engaged in erythropoiesis is:
A. hepcidin
B. transferrin
C. ferritin
D. hemosiderin
53. In healthy humans, iron in tissues other than red blood cells is stored principally in combination with:
A. ferritin
B. transferrin
C. hepcidin
D. hemosiderin
54. Which of the following statements regarding the thermic effect of feeding is incorrect?
A. It is most prominent at the time of eating.
B. It is aka specific dynamic action of food.
C. It is greater following a protein meal.
D. It is enhanced by sympathetic neural activity.
55. Normally, most of the water in the GI lumen is absorbed from:
A. stomach
B. duodenum
C. jejunum
D. colon
56. The Oral Rehydration Solution is helpful in rehydration in diarrheas because:
A. Na-glucose symporter is unaffected in toxigenic diarrheas
B. 1Na-1K-2Cl symporter is located only in the basolateral membrane
C. cAMP regulated Cl secretion is reduced
D. toxins inhibit facilitated glucose transport
57. The most frequent type of movement in the small intestine in the digestive state is:
A. peristalsis
B. antiperistalsis
C. slow wave
D. segmentation contraction
58. The pattern of intestinal motility that hastens transit of chyme in the small intestine in the digestive state is:
A. peristalsis
B. segmentation contraction
C. tonic contraction
D. migrating motor complex
59. Select all correct answers. The type(s) of contraction that normally occur(s) only in the colon is/are:
A. peristalsis
B. antiperistalsis
C. segmentation
D. mass action contraction (mass peristalsis)
60. The pattern of electrical and motor activity in the gastrointestinal tract during periods of fasting is called:
A. basic electrical rhythm
B. migrating motor complex
C. peristalsis
D. segmentation
61. Enterocytes are replenished by mitotically active undifferentiated cells located in:
A. Brunner’s glands
B. crypts of Lieberkuhn
C. Peyer’s patches
D. gut associated lymphoid tissue
62. Which of the following cells sample the antigenic milieu of the gastrointestinal lumen?
A. P cells
B. I cells
C. K cells
D. M cells (microfold cells)
E. Mo cells
63. In healthy humans, active absorption of bile acids and bile salts occurs mainly in the:
A. duodenum
B. jejunum
C. terminal ileum
D. colon
64. Select all correct answers. Calcium absorption from the intestine:
A. is facilitated by vitamin D
B. is decreased by phytates and oxalates
C. occurs mainly in the upper small intestine
65. Vitamin B12 is mainly absorbed in the:
A. terminal ileum
B. upper jejunum
C. duodenum
D. stomach
66. In healthy humans, the earliest the first part of a test meal reaches the cecum is in about:
A. 4 hours
B. 6 hours
C. 9 hours
D. 12 hours
67. Normally, the main function of the colon is absorption of:
A. Na, Cl and H2O
B. triacylglycerols
C. secondary bile acids
D. iron
68. Normally, there is a net secretion of which ion in the colon?
A. Sodium
B. Potassium
C. Chloride
D. Calcium
69. The defecation reflex is integrated in the:
A. brain stem
B. pons
C. medulla
D. spinal cord
70. The odor of feces is partly due to:
A. stercobilinogen
B. indole, skatole and sulfides
C. primary bile acids
D. secondary bile acids
