GI Physiology MCQs



GI Physiology MCQs

20th February 2007

1. All of the following are correct statements about pancreatic exocrine secretion EXCEPT

a. Bicarbonate rich fluid is secreted by ductal epithelial cells in response to secretin

b. Secretion of enzymes by acinar cells occurs in response to CCK

c. Vagotomy augments secretion of enzymes after a meal

d. Secretin and CCK both act via formation of cyclic nucleotide 2nd messengers

e. Gastrin stimulates both enzyme and bicarbonate secretion

2. The major mechanism for absorption of sodium from the small intestine is

a. Non electrolytic cotransport

b. Cotransport with potassium

c. Electrogenic transport

d. Neutral NaCl absorption

e. Solvent drag

3. All of the following statements about bile acids are correct EXCEPT

a. Bile acids are secreted as conjugated bile salts by the liver

b. Bile acids are dehydroxylated by intestinal bacteria

c. Bile acids are absorbed in the intestine and return to the liver via the portal vein

d. Bile acids facilitate absorption of fat by emulsifying glycerides

e. Sulfation of bile acids promotes their uptake in the intestine

4. Dietary fat is absorbed chiefly in the

a. Stomach

b. Jejunum

c. Ileum

d. Caecum

e. Ascending colon

5. Gallbladder contraction is controlled primarily by the hormone

a. Enterogastrone

b. CCK

c. Insulin

d. Secretin

e. Glucagon

6. All of the following statements about somatostatin are true EXCEPT

a. It inhibits gastrin secretion

b. It is secreted by the hypothalamus

c. It is secreted by pancreatic islet cells

d. It is released following vagal blockade

e. Its effects are prolonged

7. Compared with the resting state – during prolonged exercise the caloric needs of skeletal muscle are met by

a. Release of free fatty acids from adipose tissue

b. An increase in hepatic glycogenolysis

c. An increase in gluconeogenesis in muscle

d. Increased intestinal uptake of glucose and amino acids

e. None of the above

8. Binding of a peptide hormone to its receptor may involve all of the following EXCEPT

a. Reversible hydrophobic interactions

b. Allosteric regulation

c. Hydrogen bonding

d. Formation of covalent linkages

e. Coupling with an activity site

9. Secretion of pancreatic polypeptide is

a. Subsequent to its cleavage from proinsulin in the ( cell

b. A response to both vagal and ( adrenergic stimulation

c. The stimulator of release of pancreatic enzymes in response to glucose

d. Inhibited by exercise

e. None of the above

10. Activation of hormone sensitive lipase in adipocytes

a. Causes increased hydrolysis of cholesterol esters

b. Is mediated by a cAMP dependent protein kinase

c. Is prevented by cortisol

d. Is stimulated by insulin

e. Results in accumulation of monoglycerides and diglycerides in adipocytes

11. All of the following statements about the uptake of triglycerides into adipose tissue from plasma lipoproteins are true EXCEPT

a. It is regulated by the activity of lipoprotein lipase

b. It is decreased by catecholamines

c. It is increased by glucose

d. It is increased by insulin

e. It requires receptor mediated endocytosis

12. The islets of Langerhans are characterised by

a. Being more plentiful in the head of the pancreas than in the tail

b. Constituting 20 – 30% of the weight of the pancreas

c. Containing at least 6 distinct cell types

d. Having a meagre blood supply

e. Producing glucagon and insulin

13. Dietary fat, after being processes, is extruded from the mucosal cells of the GI tract into the lymphatic ducts in the form of

a. Monoglycerides

b. Diglycerides

c. Triglycerides

d. Chylomicrons

e. Free fatty acids

14. The rate of gastric emptying is influenced by all of the following factors EXCEPT

a. Carbohydrate in gastric contents

b. Secretion of gastrin by antral G cells

c. Distension of the duodenum

d. Osmolarity of duodenal contents

e. Acidity of chime entering the duodenum

15. Gas within the colon is primarily derived from which one of the following sources

a. CO2 liberated by the interaction of HCO3- and H+

b. Diffusion from the blood

c. Fermentation of undigested oligo saccharides by bacteria

d. Swallowed atmospheric air

e. None of the above

16. Vitamins synthesised by intestinal bacteria and absorbed in significant quantities include

a. Vitamin B6

b. Vitamin K

c. Thiamine

d. Riboflavin

e. Folic acid

17. Which one of the following statements about the colon is correct

a. Absorption of Na+ in the colon is under hormonal (aldosterone) control

b. Bile acids enhance absorption of water from the colon

c. Net absorption of HCO3- occurs in the colon

d. Net absorption of K+ occurs in the colon

e. The luminal potential in the colon is positive

18. Absorption of fat soluble vitamins requires

a. Intrinsic factor

b. Chymotrypsin

c. Pancreatic lipase

d. Pancreatic amylase

e. None of the above

19. Contraction of the gallbladder is correctly described by which one of the following statements

a. It is inhibited by a fat rich meal

b. It is inhibited by the presence of amino acids in the duodenum

c. It is stimulated by atropine

d. It occurs in response to CCK

e. It occurs simultaneously with the contraction of the sphincter of oddi

20. Which of the following is a paracrine secretion

a. CCK

b. Gastrin

c. Histamine

d. Secretin

e. None of the above

21. Acidification of the duodenum will

a. Decrease pancreatic secretion of bicarbonate

b. Increase secretion of gastric acid

c. Decrease gastric emptying

d. Increase contraction of the gallbladder

e. Increase contraction of the sphincter of oddi

22. In contrast to secondary oesophageal peristalsis, primary oesophageal peristalsis is characterised by which of the following statements

a. It does not involve relaxation of the lower oesophageal sphincter

b. It involves contraction of oesophageal smooth muscle

c. It is not influenced by the intrinsic nervous system

d. It has an oropharyngeal phase

e. None of the above

23. The stimulation of release of pancreatic secretions normally involves all of the following EXCEPT

a. Ach

b. CCK

c. Histamine

d. Neural stimulation

e. Secretion

24. Intestinal proteolysis is accomplished by all of the following EXCEPT

a. Carboxypeptidase

b. Chymotrypsin

c. Elastase

d. Pepsin

e. Trypsin

25. The concept that active transport is the mechanism for absorption of monosaccharides in the gut is supported by all of the following statements EXCEPT

a. Transport can be blocked by metabolic inhibitors

b. Transport is selective for different sugars

c. A maximum rate of transport exists for individual monosaccharides

d. Competition exists among sugars for the carrier mechanism

e. Transport can occur bidirectionally

26. Removal of the terminal ileum will result in

a. A decrease in absorption of amino acids

b. An increase in the water content of the faeces

c. An increase in the concentration of bile acid in the enterohepatic circulation

d. A decrease in the fat content of the faeces

e. An increase in the absorption of iron

27. All of the following statements concerning normal human pancreatic juice are true EXCEPT

a. Its pH is approximately 8.0

b. It has a high bicarbonate content

c. Over 1000ml are secreted per day

d. It contains cholesterol esterase

e. Its secretion is primarily under neural control

28. Mass movements (strong peristalsis) in the colon would be abolished by

a. Vagotomy

b. Extrinsic denervation

c. Distension of the colon

d. Destruction of Meissner’s plexus

e. Destruction of Auerbach’s plexus

29. Saliva has all the following constituents EXCEPT

a. Bicarbonate

b. Phosphate

c. Chloride

d. Glucose

e. Lysozyme

30. Where are vitamins A, D and K absorbed

a. Stomach

b. Proximal small bowel

c. Terminal ileum

d. Duodenum

e. Ascending colon

31. Regarding carbohydrate metabolism – which of the following statements is correct

a. About 80% of energy supplies are stored in fat

b. Most of the glycogen stores are in the liver

c. Resting muscle utilises glucose for its metabolism

d. At rest – the brain accounts for 40 – 50% of glucose utilised

e. 5% of ingested glucose is promptly converted to fat

32. Regarding basal metabolic rate – all are true EXCEPT

a. It is relatively higher in women than men

b. It falls about 10% during sleep

c. It is increased by tension

d. It falls about 40% during prolonged fasting

e. It increases in high and low environmental temperatures

33. All of the following increase gastrin secretion EXCEPT

a. Calcium

b. Luminal peptides and amino acids

c. Secretin

d. Epinephrine

e. Increased vagal discharge

34. Regarding GI hormones

a. Luminal somatostatin inhibits gastrin secretion

b. CCK secretion is increased by the presence in the duodenum of fatty acids containing more than 3 carbon atoms

c. GIP is produced by the ileum

d. Secretin increases the section of an enzyme rich pancreatic juice

e. VIP causes contraction of intestinal smooth muscle

35. Regarding the principal lipoproteins

a. Chylomicrons originate in the liver

b. IDLs are 40% phospholipids

c. LDLs are 20nm in size

d. HDLs are 25% protein

e. VLDLs are 6% triglyceride

GI Physiology MCQs

21st February 2006

Answers

1. C

2. D

3. E

4. B

5. B

6. E

7. B

8. D

9. B

10. B

11. E

12. E

13. D

14. A

15. C

16. E

17. A

18. C

19. D

20. C

21. C

22. D

23. C

24. D

25. E

26. B

27. E

28. E

29. D

30. B

31. A

32. A

33. C

34. A

35. C

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