MCQs - physiology - GIT

Digestive system

1- As regards salivary secretion, all are true EXCEPT:
a) Comes mostly from the parotid, submandibular & sublingual glands.
b) Has a mucous component.
c) Has a serous component.
d) Is largely under hormonal control.

2- Concerning salivary secretion, all are true EXCEPT:
a) Is entirely under neural control.
b) Has a constant composition regardless of the rate of secretion.
c) Contains salivary amylase.
d) Is important in keeping the mouth and throat moist at all times.

3- The saliva:
a) Contains no organic substances.
b) Is markedly increased in amount after sympathetic stimulation.
c) Secretion is increased after injection of atropine.
d) Secreted by the submandibular glands is about 70% of the total secretion.

4- Saliva is characterized by all the following EXCEPT:
a) Its concentration of K+ is the same as that in the plasma.
b) Its Na+ & Cl– concentrations are lower than those in the plasma.
c) Its osmotic pressure & pH are lower than their corresponding values in the plasma.
d) It exerts an antibacterial action.

5- The act of the swallowing is associated with:
a) Movement of food into the nasopharynx.
b) Opening of the glottis.
c) Inhibition of respiration.
d) Constriction of the upper esophageal sphincter.

6- Deglutition is accompanied by all of the following EXCEPT:
a) Relaxation of the upper esophageal sphincter.
b) Contraction of the pharyngeal wall muscles.
c) Closure of the larynx by epiglottis.
d) Pulling the soft palate downwards.

7- The process of swallowing (deglutition):
a) Consists of 5 phases all of which are involuntary.
b) Can easily occur while the mouth is open.
c) Is controlled by a centre in the medulla & lower pons that initiates a peristaltic wave in the pharyngeal musculature.
d) In the buccal phase the tongue moves downwards and the larynx is depressed.

8- The primary esophageal peristalsis differs from the secondary peristalsis in that the former:
a) Occurs after the latter.
b) Is independent of neural control.
c) Is initiated by swallowing.
d) Is confined to the upper part of the esophagus.

9- About the process of swallowing, all the following is true EXCEPT:
a) As a peristaltic wave passes along the esophagus, the cardiac sphincter & stomach wall relax.
b) The esophageal musculature below the pharynx contains skeletal (striated) muscle which entirely under control of the vagi nerve.
c) Food doesn’t enter the trachea mainly due to approximation of the vocal cords.
d) The voluntary phase includes the period during which food passes through both the buccal cavity and pharynx.

10- The salivary secretion:
a) Is produced by a nervous mechanism only.
b) Digests starch to glucose.
c) Has the largest volume relative to other digestive juices.
d) Is hyperosmotic relative to the plasma.

11- The salivary secretion:
a) Has a constant composition regardless the rate of secretion.
b) Is a simple process of filtration of the plasma.
c) Is entirely under neural control.
d) Is under control of the cerebral cortex only.

12- Gastric secretion is increased by:
a) Sympathetic stimulation.
b) Acid in the duodenum.
c) Stimulation of stretch receptors in the wall of the stomach.
d) Heypertonicity of duodenum.

13- Concerning hydrochloric acid secretion, all are true EXCEPT:
a) Is secreted by parietal cells in the stomach.
b) Its secretion can be stopped by H2 receptor blocking.
c) Gastrin, acetylcholine & histamine can stimulate its secretion.
d) Occurs due to passive diffusion of H+.

14- Hydrochloric acid secretion by parietal cells:
a) Requires dissociation of water with subsequent exchange of H+ with Na+.
b) H+ is actively secreted into the canaliculus in exchange for K+.
c) Cl– enters the parietal cell in exchange for Na+ ions.
d) No energy is needed for this process.

15- As regards gastrin hormone, all are true EXCEPT:
a) Increased HCl secretion.
b) Is released by vagal stimulation.
c) Is released by stomach distention.
d) Presence of acid in the stomach stimulated its release.

16- Concerning secretin hormone, all are true EXCEPT:
a) Increases pancreatic secretion of HCO3–.
b) Causes contraction of pyloric sphincter.
c) Augments the action of CCK in producin pancreatic secretion rich in enzymes.
d) Is secreted by the pancreas.

17- Secretin hormone:
a) Is released when fat is present in small intestine.
b) Causes contraction of the gall bladder.
c) Decreases gastric acid secretion & motility.
d) Stimulates pancreatic secretion of insulin.


18- As regards cholecystokinin (CCK), all are true EXCEPT:
a) Products of protein digestion stimulate its release.
b) Causes contraction of the all bladder and relaxion of sphincter of Oddi.
c) Increase gastric motility and secretion.
d) Causes secretion of pancreatic juice rich in enzymes.

19- Concerning vomiting, all are true EXCEPT:
a) Is a forceful expulsion of the gastric contents through the mouth.
b) Is a complex reflex act, which is coordinated by vomiting centre in the medulla.
c) Results in loss of fluid which may lead to circulatory collapse.
d) Accompanied by elevation of diaphragm to squeeze out the gastric contents.

20- Concerning regulation of pancreatic secretion:
a) Presence of food in the stomach directly increases pancreatic secretion.
b) Sight or smell does not affect pancreatic secretion.
c) CCK augments the action of secretin in producing pancreatic secretion rich in HCO3–.
d) Pancreatic secretion is entirely under hormonal control.

21- In the stomach:
a) Secretion of enzymes is by parietal (oxyntic) cells.
b) Secretion of acid is from parietal cells.
c) Gastrin is secreted by the same cells that secrete acid.
d) The main digestive function is the breakdown of charbohydrates.

22- Concerning salivary amylase, all are true EXCEPT:
a) Is secreted mainly by the parotid glands.
b) Is a protein in nature.
c) Is secreted in response to parasympathetic stimulation.
d) Is most active at pH 1-2.

23- Function of the stomach include the following, EXCEPT:
a) Storage of food during digestion.
b) Secretion of intrinsic hemopoietic factor into the lumen.
c) Secretion of secretin into the blood.
d) The maintenance of iron in the ferrous state.

24- Gastric emptying is delayed by all the following EXCEPT:
a) Vagotomy.
b) Fat in the duodenum.
c) Secretin.
d) Increased fluidity of the chyme.

25- Gastric emptying:
a) Is slowest if the food is soft and rich in carbohydrates.
b) Is inhibited by excessive acidity in the duodenum.
c) Is accelerated by presence of fat or hypertonic solutions in the duodenum.
d) Is delayed by distension of the stomach and by vagal stimulation.

26- HCl secretion includes all the following processes EXCEPT:
a) Active transport of H+ into the gastric lumen.
b) H+ is exchanged for K+ from the extracellular fluid.
c) HCO3– diffuses into the extracellular fluid in exchane for Cl–.
d) It is associated with production of postprandial alkaline tide.

27- The cephalic phase of gastric secretion:
a) Occurs when food reaches the stomach.
b) Is not accompanied by release of GRP (gastrin-releasing peptide).
c) Is controlled by the vagi nerves.
d) Is not blocked by injection of atropine.

28- The gastric juice has all the following characteristics EXCEPT:
a) It contains an alkaline secretion from the surface epithelium.
b) Its pH is always less than 3.
c) It contains the intrinsic factor which is essential for vitamin B12 absorption.
d) Its antibacterial action is produced by its mucus content.

29- Gastric secretion is inhibited by all the following EXCEPT:
a) Presence of excess protein digestive products in the stomach.
b) Certain emotions e.g. fear & depression.
c) Certain GIT hormones e.g. secretin, CCK & VIP.
d) The enterogastric reflex.

30- Stomach emptying is delayed by all the following EXCEPT:
a) Certain GIT hormones e.g. secretin, CCK & GIP.
b) Presence of excess fat in the meal.
c) Moderate gastric distention.
d) The enterogastric reflex and bilateral vagotomy.

31- About the gastric motility, all the following is true EXCEPT:
a) It increases by the vagal stimulation & decreases by symp. stimulation.
b) It decreases by the enterogastric reflex and by the secretin & CCK hormones.
c) It increases by overdistention of the stomach.
d) It decreases in response to presence of excess fat in the duodenum.

32- Gastric HCl secretion:
a) Occurs secondary to active transport of H+ by the parietal cells into the lumen of the stomach.
b) Is increased by administration of histamine.
c) Is inhibited by the secretin hormone & H2 receptor blockers (e.g. cimetidine).
d) All of the above.

33- The act of vomiting:
a) is produced mainly by contraction of the gastric musculature.
b) May be associated with reverse peristalsis in the esophagus.
c) May lead to respiratory alkalosis (if prolonged).
d) Is coordinated by a centre in the sacral region of the spinal cord.

34- Which of the following statements is true?
a) The intrinsic factor is secreted by the parietal cells of the gastric mucosa.
b) The stomach normally absorbs about 30% of the ingested food.
c) The secretion of gastric juice is associated with increased H+ in the blood.
d) The gastric juice is essential for the digestion of both fat & protein.

35- Concerning HCl secretion, all the following is true EXCEPT:
a) It is associated with increased pH of the gastric venous blood.
b) It is stimulated by gastrin, acetylcholine, histamine & norepinephrine.
c) The energy required is derived from ATP breakdown.
d) There is an active transport of H+ from the oxyntic cells into the gastric lumen and K+ in the opposite direction.

36- Concerning pancreatic juice:
a) Gastrin is an important stimulant of secretion of bicarbonate by the pancreas.
b) Secretin inhibits the secretion of pancreatic juice.
c) Cholecystokinin (CCK) stimulates the secretion of pancreatic enzymes.
d) Sight or smell of food does not affect pancreatic secretion.

37- Concerning the pancreas, all are true EXCEPT:
a) It is an exocrine organ.
b) It is an endocrine organ.
c) It receives innervation from the autonomic nervous system.
d) Increase in secretion is accompanied by vasoconstriction of pancreatic arterioles.

38- Secretin:
a) Acts as a powerful cholagogue.
b) Is secreted as a result of vagus nerve stimulation.
c) Stimulates gastric secretion.
d) Is released as a result of contact of acid chyme to the duodenal mucosa.

39- About CCK, all the following is true EXCEPT:
a) It causes contraction of the gallbladder wall.
b) It produces a pancreatic secretion rich in enzymes.
c) It potentiates the action of secretin on the pancreas.
d) It inhibits both gastric and intestinal motility.

40- The pancreatic secretion:
a) Is the primary source of HCO3– for neutralization of HCl in the intestine.
b) Is secreted by the pancreatic acini only.
c) Is the least important digestive juice.
d) Is associated with rise of the blood pH.

41- Concerning bile and bile salts, all are true EXCEPT:
a) Bile salts are emulsifying agents.
b) Bile are concentrated in the gall bladder.
c) Bile salts promote lipid absorption by forming water soluble micells.
d) Its secretion from the liver is intermittent.

42- Bile salts:
a) Are derived from hemolysed RBCs.
b) Breakdown fats to fatty acids.
c) Are among the most important physiologic cholertics.
d) Are essential in digestion of carbohydrates.

43- As regards contraction of the gall bladder:
a) It is stimulated by a fat-rich meal or amino acids in the duodenum.
b) It is stimulated by atropine.
c) It occurs in response to cholecystokinin.
d) It occurs simultaneously with the contraction of the sphincter of Oddi.

44- All the following statements about cholecystokinin (CCK), are true EXCEPT:
a) CCK is released by fat in the small intestine.
b) CCK increases pancreatic enzyme secretion.
c) CCK contracts sphincter of Oddi.
d) CCK decreases gastric emptying.

45- The stimulation of release of pancreatic secretions normally involves all the following EXCEPT:
a) Acetyl choline.
b) Cholecystokinin.
c) Histamine.
d) Secretin.

46- The bile salts:
a) Are essential for absorption of proteins.
b) Are essential for absorption of vitamins A, B & C.
c) Are concentrated in the gall bladder.
d) Are not reabsorbed from the small intestine.

47- All the following increase bile secretion from the liver EXCEPT:
a) Secretin.
b) CCK.
c) Increased hepatic blood flow.
d) The enterohepatic circulation of the bile salts.

48- Obstructive jaundice:
a) Results from excessive destruction of the RBCs.
b) Involves excretion of urine having a normal colour.
c) Involves excretion of stools darker than normal.
d) Causes excess fat loss in the stools.

49- An obstruction of the common bile duct:
a) Does not affect absorption of vitamins.
b) Leads to clay-coloured stools.
c) Causes increased formation of prothrombin by the liver.
d) Causes no change in the normal colour of urine.

50- In hepatic jaundice:
a) Both haemobilirubin & cholebilirubin blood levels are decreased.
b) The liver functions are depressed & the plasma albumin level is decreased.
c) The urine colour is normal while that of the stools is darker than normal.
d) Fat digestion & absorption are not affected.

51- Concerning obstructive jaundice:
a) Van-den Berg reaction is biphasic.
b) Is accompanied by tachycardia and itching.
c) The colour of the stool is darker than normal due to high content of strecobilin.
d) Is accompanied by steatorrhea.

52- Concerning hepatic jaundice:
a) The urine is dark due to increased urobilinogen.
b) It is due to increased hemolysis of RBCs.
c) Van-den Berg reaction shows only direct response.
d) Fat digestion and absorption is decreased.

53- Concerning cholagogues and choleretics:
a) Secretin hormone is a cholagogue.
b) Mg sulfate increases hepatic bile formation.
c) CCK-PZ is a choleretic.
d) Bile salts increase hepatic bile formation.

54- Concerning bile salts:
a) They have no role in digestion and absorption of fat.
b) They inhibit pancreatic lipase.
c) They have a solvent effect on cholesterol preventing its precipitation.
d) They are completely excreted in stools.

55- The segmentation (mixing) movements in the GIT:
a) Occur only in the small intestine.
b) Depend on the extrinsic autonomic nerve supply.
c) Are increased by injection of atropine.
d) Are greatly helpful for the process of absorption.

56- The peristalsis in the small intestine:
a) Can occur in absence of the local nerve plexus.
b) Is myogenic in origin.
c) Plays a minimal role in food propulsion.
d) Is commonly reversed (antiperistalsis) in the duodenum & lower ileum.

57- Concerning absorption:
a) Short-chain fatty acids are absorbed through lacteals.
b) Bile salts of no importance in fat digestion and absorption.
c) Steatorrhea means increased protein content in stool.
d) Steatorrhea occurs in obstructive jaundice & severe pancreatic disease.

58- Concerning large intestine:
a) It contains villi for absorption.
b) Distention of proximal colon initiates defecation.
c) Ammonia can be formed from bacteria.
d) Digestion of cellulose occurs in human.

59- Defecation:
a) It is under voluntary control in infants.
b) During rest, the rectum is distended.
c) It is delayed by gastric colic reflex.
d) It occurs more likely just after meals.

60- In the colon, all are true EXCEPT:
a) Bacterial synthesis of vitamin K is of vital importance.
b) More than half of the water that enters the colon is absorbed from the contents.
c) Sympathetic stimulation results in enhanced motility.
d) The secretion lacks significant digestive enzymes.

61- The ileum is the principle site for the absorption of:
a) The products of fat digestion.
b) Bile salts.
c) Vitamin K.
d) Iron.

62- In infants, defecation follows a meal, the cause of colonic contraction in this situation is:
a) Gastroileal reflex.
b) Gastrocolic reflex.
c) Enterogastric reflex.
d) Increased circulating level of CCK.