NDM Trefor Morgan Gastrointestinal Questions

1

Which of the following structures is not pan of the gastrointestinal tract?


  pharynx

  larynx

  caecum

  stomach

  oesophagus


The larynx together with he epiglottis isolates the respiratory system from the gastrointestinal tract and is part of the respiratory system.

2

Which of the following pressure profiles (mmHg) best represents the pressure profile from the pharynx to the stomach inclusive at rest?


  20 40 20 10 0

  40 20 0 10 0 c. 0 40 0 30 0

  0 100 0 100 0

  0 40 20 40 0


When a person is at rest there is no effective pressure in the pharynx. The upper sphincter of the oesophagus closes the oesophagus and has a pressure of approximately 40 mmHg. In the body of the oesophagus the pressure is close to atmospheric (i.e. zero) while at he lower sphincter of he oesophagus there is a pressure of approximately 30 mmHg. The pressure in the stomach is close to zero.

3

Which of the following pressure profiles (mmHg) best reprcscnis the pressure profile from the pharynx 10 the stomach inclusive approximately 6 seconds after swallowing?


  0 100 100 100 0

  0 40 40 20 0 c. 40 0 40 30 0

  0 40 100 30 0

  0 40 100 0 0


When a person swalows, th eperistaltic wave moves at a rate of approximately 2cm per second from just below the upper sphincter of the oesophagus. In the initial act of swalloing there would be an inrease in pressure in pharynx, followed at the same time by a relaxation of the uper sphincter of the oesophagus and a fall in pressure to pproximately zero but with 6 seconds this hsa dissipated. The sphincter closes and overshoots wth a high pressure of about 60 mmHg and then returns to its baseline pressure of approximately 40 mmHg. A wave of pessure moves down te oesophagus in a peristaltic movement. The lower sphincter ofthe oesophagus relaxes approximate 3-4 seconds after te swalloing reflex is commenced. Thus it drops to zero ebfore the pressure wave getsthere and the presure in the stomach is close to zero.

4

Which one of the following statements related to peristalsis in the small intestine is most accurate?


  There is simultaneous contraction of circular and longitudonal muscle allowing progression.

  Peristalsis is initiated by distension of the intestinal wall.

  Peristalsis is initiated hy increased vagal activity.

  Motilin decreases the rate of peristalsis.

  Peristalsis is the predominant contractile activity in the small intestine.


Peristalsis is initiated by distension of the small intestine wall and is mediated by the myenteric plexus. Vagal activity may influence and increase peristalsis but does not initiate it. otilin may increase intestinal movement. Peristalsis involves contraction of the longitudonal muscle followed by circular muscle contraction, but these occur 90 degrees out of phase. Segmented contraction of teh small intestine is more common than peristalsi and mixes the food.

5

All of the following statements related to acetyl choline are correct except for:


  Is released by the vagus nerve.

  Potentiates the effect of secretin on HC03- secretionby the pancreas.

  Acts on peptic cells to increase acid secretion.

  Increases gastric smooth muscle contractility.

  Increases firing frequency of pacemaker of stomach.


Acetyl choline is released by the vagus nerve and has a number of effects on gastrointestinal function. Acety chline increases the firing rate of the stomach pacemaker and increases the contractility of stomach muscle fibres. It potentiates the action of secretin on secretion of HCO3- from the pancreas. It does have effects on the gastric gland increasing acid secretion from the parietal (oxyntic) cells. However the peptic (chief) cells do not secrete acid.

6

All of the following statements related to the vagus nerve or acetyl choline are correct except for:


  The vagus nerve mediates the cephalic phase of gastric secretion.

  Increased vagal activity increases secretion from pancreatic acinar cells.

  Increased vagal activity increases gastrin release.

  Acetyl choline is released by local enteric nerves.

  Increased vagal activity decreases tone of the pylorus.


Acetyl choline is released by the local enteric nerves together with other substances. Vagal nerve activity increases secretion of gastrin and has a direct effect on the gastric gland and these effects mediate the cephalic phase of gastric secretion. When different vagal activity is intiated it increases secretion (enzymes) from the panreatic acinar cell. It increases contratilty of the gastric muscle, including that of the pylorus, thus increased vagal activity increases not decreases pyloric tone.

7

All of the following statements related to acetyl choline are correct except for:


  Is released by vagus nerve

  Reduces peristaltic activity.

  Is released by local enteric nerves.

  Increases secretion from pancreatic acinar cells.

  Acts on peptic cells to increase pcpsinogcn secretion.


See Questions 5 and 6 Acetyl choline acts on the peptic (cief) cells to increase pepsinogen secretion. Acetyl choline increases peristalsis, not decreases it.

8

All of the following statements related to acid secretion from the stomach are correct except for:


  Acid secretion is increased by gastrin.

  Acid secretion is increased by histamine.

  Acid secretion is increased by acetyl choline.

  Acid secretion is increased by antral lumen pH < 3.5.

  Acid secretion is increased by increased vagal activity.


Acid secretion of the oxyntic (parietal) cells of the gastric gland is directory or indrectly increased by histamine, gastrin, acetyl choline and increased vagal activity which cases release of acetyl choline and gastrin. Gastrin secretion from the antrum is, however, decreased by low pH and thus acid secretion is reduced. Low pH in the antrum also causes somatostatin release, which inhibits acid secretion.

9

All of the following statements related to acid secretion from the stomach are correct except for:


  Is increased by PGE1.

  ls controlled by the endocrine cell of the gastric gland.

  Is secreted by the oxyntic (parietal) cell.

  Is inhibited by anu·al luminal pH < 3.5.

  Is increased by protein digestion products in the antrum.


The gastric gland endocrine cell (ECL) releases histamine in a high local concentration and this stimulates acid secretion from the oxyntic (parietal) cell. Gastrin, which acts on the gastric gland endocrine cell to release histamine, has its release increased from intestinal endocrine cells if there arc protein digestion products in the duodenum. If the pH of the antrum falls below 3.5 gastrin secretion is inhibited and somatostatin, which inhibits acid secretion, is released. PGE1 acts on the oxyntic cells to decrease cyclic AMP production and thus reduces the proton pump activity and inhibits acid secretion.

10

All of the following statements related to acid secretion from the stomach are correct except for:


  Is decreased by sodium bicarbonate in the stomach.

  ls increased by H2 receptor agonists.

  Is increased hy protein digestion products in the dl!lxknum.

  The effects of acetyl choline and gastrin are additive.

  The effects of acetyl choline and histamine are additive.


Histamine acts on the oxyntic cells to increase cyclic AMP which activates the proton pump. Acetyl choline acts by increasing calcium influx, which also increases pump activity. Thus the effects of acetyl choline and histamine additive. As gastrin works via histamine (see Question 9) the effects of acetyl choline and gastrin are also additive. Histamine has two types of receptors and it acts on H2 receptors in the oxyntic cell to increase acid secretion. Protein products in the duodenum cause acid secretion by releasing intestinal gastrin. Sodium bicarbonate will increase the pH in the stomach and thus gastrin secretion from the antrum will not be inhibited and therefore acid secretion will go up. However, the pH in the stomach is notas low as usual due to neutralisation of the H+ secretion.

11

All of the following statements related to acid secretion from the stomach are correct except for:


  Acid secretion is decreased by H2 receptor antagonists.

  Acid secretion is increased by H1 receptor agonists.

  Acid secretion is increased by stomach distension.

  Acid secretion depends upon H+ ATPase.

  Acid secretion is increased by mucosal damage.


Acid secretion depends on H+ ATPase. Distension of the stomach activates local enteric reflexes and increases gastrin secretion. Thus acid secretion also increases. Mucosal damage may release histamine, which increases acid secretion. Histamine acts via H2 receptors. Thus an H2 receptor antagonist will inhibit secretion, but an H2 receptor agonist has a net stimulatory effect.

12

All of the following statements related to Lhc actions of gastrin are correct except for:


  Gastrin increases pepsinogen secretion.

  Gastrin stimulates histamine release.

  Gastrin increases stomach contractility.

  Gastrin increases gastro-oesophagal sphincter tone.

  Gastrin increases acid secretion.


Gastrin released from the antral G cells acts on the gastric endocrine cell to stimulate histamine release, which increases acid secretion. It also acts on stomach muscle cells increasing the contractility. and also increases pyloric and gastro-oesophageal tone. It has no effect on pepsinogen secretion from the peptic cell.

13

All of the following statements related to gastrin secretion and its actions are correct except for:


  Gastrin secretion is stimulated by protein breakdown products.

  Gastrin secretion is stimulated by vagal activity.

  Gastrin stimulates oxyntic (parietal) cell growth.

  Gastrin reduces contractility of the stomach.

  Gastrin is a competitive inhibitor of cholecystokinin.


Gastrin release is increased by vagal activity and by protein breakdown products in the antrum. Gastrin and cholecystokinin have similarities in structure, and gastrin is a partial agonist and antagonist of cholecystokinin activity. Gastrin does have receptors on the oxyntic (parietal) cell but these do not directly cause acid secretion but rather stimulate cell growth. Gastrin increases the rate of firing of the stomach pacemaker situated on the greater curvature and increases contractility.

14

All of the following statements related to gastrin secretion are correct except for:


  Gastrin secretion is stimulated by protein breakdown products.

  Gastrin secretion is stimulated by vagal activity.

  Gastrin secretion is stimulated by GRF.

  Acetyl choline increases gastrin secretion.

  pH < 3 in gastric antrum increases gastrin secretion.


More gastrin is released when vagal activity is increased and this is mediated viat he release of acetyl choline. Endocrine cells in the antrm also release gsatrin releasing factor (GRF) which increases gastrin release. A low pH (i.e. high H+ concentration) inhibits gastrin release directly and by the release of somatostatin.

15

All of the following statements related to pancreatic secretions are correct except for:


  pH is approximately 8.0.

  Less than 1000 mL is secreted per day.

  Contains trypsinogen.

  Acinar cell secretion is stimulated by cholecystokinin.

  Insulin is secreted from β cells.


The pancrease secretes morethan 1000 mL of pancreatic juice each day. he juice has an alkaline pH and contains trypsinogen, which is activated in the intestine. The acinar cels secrete the enzymes and this secretion is stimulated by cholecystokinin. Ifthe blood glucose level is low, insulin is secreted from the β cells of the Islets of Langerhans.

16

All of the following statements related to pancreatic secretions are correct except for:


  Contains a lipase.

  Contains carboxypeptidase.

  Carboxypeptidase is an exopeptidase.

  Secretion of bicarbonate is stimulated by cholecystokinin.

  Bicarbonate content is high.


The pancreas secretes a vaJicty or enzymes including lipase and carboxypeptidase, which is an exopeptidase (i.e. breaks off the end amino acids ). The pancreatic duct cells secrete bicarbonate and thus the pH is > 7.0. Bicarbonate secretion is stimulated by sccretin. Cholecystokinin stimulates acinar cell (enzyme) secretion.

17

All of the following statements related to pancreatic secretions are correct except for:


  Enzymes are released by exocytosis.

  Contains trypsinogen.

  Trypsin is activated in the pancreas.

  Trypsin is an endopeptidase.

  Contains a trypsin inhibitor.


Trypsin is the major proteolytic enzyme. lt is secreted as trypsinogcn by exocytosis from the acinar cells. It is an endopeptidase. Pancreatic juice contains a trypsin inhihitor. In addition trypsinogen is not activated while it is in the pancrease but only when it enters the duodenum by the enzyme enterokinase. If there is a reflux of duodenal contents into the pancreatic duct it may then be activated and cause autodigestion of the pancreas. Once some trypsin is formed it can then activate other trypsinogen molecules.

18

All of the following statements related to the pancreas and pancreatic secretions are correct except for:


  Acinar cell secretion is increased by vagal activity.

  Duct cell secretion is increased by cholecystokinin.

  Pancreatic juice contains an α amylase.

  α amylase breaks down 1-4 glucoside linkage.

  Limit dextrins are formed from starch by α amylase.


Increased vagal activity increases pancreatic acinar cell secretion. One of the enzymes secreted is an α amylase which breaks down the 1-4 glucosidic bond to for limit dextrin. Cholecystokinin increases secretion or enzymes from the acinar cell but has little effect on duct cell secretion (bicarbonate).

19

All of the following statements related to digestion of fod are correct except for:


  Proteins are digested by pepsin.

  Proteins are digested by trypsin.

  Lipids are digested by intestinal lipase.

  Triglycerides are digested by lipases.

  Starches are digested by pancreatic amylase.


Starches are digested to limit dextrins and disaccharides by α amylase. Proteins are digested by pepsin and trypsin. Triglycerides are digested by lipase. However, the lipase comes from the pancrease, not from the intestine.

20

All of the following statements related to digestion of food are correct except for:


  Pepsinogen is activated by a high H+ concentration.

  Pepsin is an ndopeptidase.

  Trypsinogen is activated in the pancreas.

  Starches are broken down to limit dextrin by α amylase.

  α dextrinase breaks 1-6 glucosidic bonds.


Pepsinogen is activated by a high H+ concentration (i.e. a low pH) to pepsin which is an endopeptidase. α amylase breaks down the 1-4 glucosidic bonds to for limit dextrin, which has its 1-6 glucosidic bond broken down by α dextrinase. Trypsinogen is a precursor of a proteolytic enzyme trypsin. It is not, however, activated until it gets in the duodenal lumen. By contrast pepsinogen is activated in the lumen of the gastric gland by low local pH.

21

All of the following statements related to digestion of protein and carbohydrates are correct except for:


  Starches are digested by α amylase.

  α amylase breaks starches down to disaccharides.

  Disaccharidases are intestinal membrane enzymes.

  Pepsinogen is activated by high H+ concentration.

  Proteins are digested by carboxypeptidase.


Starches are digested by α amylase, but while disaccharides ared αdextrinases are needed to complete the berakdown as limit dextrins are formed. The disaccharidases and the αdextrinase are membrane enzymes. Pepsinogen is activated by a low pH, and carboxypeptidases are important in protein digested.

22

ALl of the following statements related to trypsinogen or trypsin are correct except for:


  Trypsinogen is activated by a high pH.

  Trypsinogen is not activated in the pancreas.

  Trypsinogen is activated by enterokinase.

  Trypsinogen is activated by trypsin

  Trypsin is an endopeptidase.


Trypsinogne is primarily activated by enterokinase (i.e. an intestinal enzyme). The trypsin produced can then activate more trypsinogen. This does not occur in the pancrease and a high pH does not activate trypsinogen. Trypsin is an endopeptidase.

23

All of the following statements relatedto absotption of food are correct except for:


  Na+ must be present for the absorption of glucose.

  Amino acid absorption is stimulated by Na+.

  Glucose is absorbed by co-transport with Na+.

  Short chain faty acids are absorbed into the lacteals.

  Chylomicrons are formed in the intestinal cell.


Sodium is absorbed in conjunction with glucose and amino acids by co-transport systems. Sodium stimulates glucose and amino acid transport and they in turn can stimulate sodium transport. When fats are absorbed into the intestal cells chylomcrons are formed, which enter the lacteals. Short chain fatty acids, however, are water soluble and can be absorbed directly ad go into the portal blood, whcih takes them to the liver.

24

All of the following statements related to the absorption of monosaccharides are correct except for:


  Glucose inhibits fructose absorption.

  Glucose inhibits galactose absorption.

  Na+ must be present for the absorptiono of glucose.

  Glucose is absorbed by secondary active transport in the small intestine.

  Glucose is absorbed by passive transport in the small intestine.


Glucose and galactose use the same Na+-sugar receptor for co-transport across the membrane and thus can inhibit each other's absorption. Fructose absorption isby an independent, non-sodium depndent pathway. Glucoseabsorption is passive when glucose content in the bowel is high, and then it stimulates sodium reabsorption. However, the the glucose concentration is low Na+ drives glucose absorption, and this is secondary active transport of glucose.

25

Which one of thefollowing statements is most accurate?


  Chylomicons are formed in the intestinal lumen.

  Chlyomicron formation depends on bile acids.

  Bile acids are essential for fatty acid absorption.

  Short chain fatty acids are absorbed into the portal blood.

  Micelles enter the circulation by the lacteals.


Micelles but not chylomicrons are formed in the intestinal lumen. Chylomicrons are synthesised in the intestinal cells and enter the lymphatics. Bile acids are neded for absorption of some lipids, but not the absorption of aty acids. Fatty acids are absorbed and short chain fatty acids enter the portal blod. Some may be resynthesised into chylomicrons inthe intestinal cells. You should note that this particular question asked "Which state is most accurate". This it is very important to always read the question correctly.

26

All of the following statements related to absorption of foods are correct except for:


  Short chain fatty acidsare absorbed into the portal blood.

  Chlomicrons are formed in the intestinal cell.

  Dipeptide absorption is stimulated by Na+.

  Amino acid absorption is stimulated by Na+.

  Disaccharides can be absorbed.


Amino acids and dipeptide absorption depends upon a Na+-amino acid or Na+-dipeptide carrier. Short chain fatty acids are absorbed by the intestinal cell and either enter the portal blood or maybe resynthesised to chylomicrons, which enter the lacteals. Disaccharides are not absorbed and need to be broken down to monosaccharides by membrane enzymes called disaccharidases. Deficit of these disaccharidase enzymes leads to accumulation of osmolytes in the intestinal lumen and diarrhoea.

27

All of the following statements related to absorption are correct except for:


  Fe3+ is preferentially absorbed compared with Fe2+

  Ascorbic acid increases iron absorption.

  Iron is best absorbed in the duodenum.

  Iron absorption is regulated.

  A low pH improves iron absorption.


Iron aborption is regulared and increases in states of iron deficiency. Usually less that 10% of iron in te diet is absorbed. Ferrous (Fe2+) salts are more soluble than ferric (Fe3+) salts and are better absorbed. AScorbic acid and a low pH convert iron into the ferrous form, and thus iron is best absorbed in the duodenum.

28

All of the following statements related to absorption are correct except for:


  Requirement for iron in women in 1-1.5 mg/day

  Dietary intake of iron in women needs to be 10-20 mg/day

  Dietary intake of calcium should be approximately 1200 mg/day

  Active vitamin D regulates calcium absorption.

  Parathyroid hormone increases Ca2+ absorption by the intestine.


Women need about 1-1.5mg/day of iron to be absorbed. As only about 10%of iron is absorbed the daily intake needs to be about 10-20mg. Calcium absorption is regulated by vitamin D and the oral intake needs to be about 1200mg/day. Parathyroid hormone has no direct effect on calcium absorption from the intestine and thus this is the wrong statement, bu parathyroid hormone may have an indirect effect by increasing active vitamin D formation via effects on the kidney.

29

All of the following statements related to the terminal ileum are correct except for:


  Vitamin D is absorbed in the terminal ileum.

  Vicamin K is absorbed in the terminal ileum.

  Vitamin A is absorbed in the terminal ileum.

  Bilirubin is absorlbed in the terminal ileum.

  Bicarbonate is secreted by the terminal ileum.


THe terminal ileum is important for the absorption of fat-soluble vitamins (i.e. A, D, K) and bile acids. Bilirubin, however, is not absorbed. The ileum also secretes bicarbonate.

30

Which one of the following statements related to the function of the terminal ileum is most accurate?


  Bicarbonate is secreted by the terminal ileum.

  Vitamin B6 is absorbed in the terminal ileum.

  Vitamin C is absorbed in the terminal ileum.

  Bilirubin is absorlbed in the terminal ileum.

  The terminal ileum is the major site of calcium absorption.


The water soluble vitamins B6 and C are absorbed before the terminal ileum. Calcium is absorbed in the jejunum. Bilirubin is not absorbed. However, bicarbonate is secreted at this site, and in some disease states increased bicarbonate secretion is excessive and will cause diarrhoea.

31

All of the following statements erlated to sodium and water reabsorption are correct except for:


  Proceeds by Na+-H+ co-transport.

  Depends on basolateral membrane Na+-K+ ATPase.

  Proceeds by Na+-glucose co-transport.

  Proceeds by Na+-H+ counter-transport.

  Proceeds by Na+-galactose co-transport.


The driving force for elctrolytic absorption is the gradient produced by basolateral Na+-K+ ATPase. Na+ enters the membrane by Na+-glucose. Na+-galactose co-transport and by Na+-H+ counter-transport. Thus Na+-H+ co-transport is the incorrect statement.

32

All of the following statements related to eletrolytes and water reabsorption are correct except for:


  Decreased by osmolytes in the intestine.

  Increased bycyclic AMP in the cell.

  Decreased by icnreased levels of cyclic GMP.

  Decreased by increased levels of 'free calcium' in the cystosole.

  Decreased by cholera toxin.


Increased levels of cyclic AMP in the cell decrease absorption of NaCl and electrolytes. Cholera toxin increasesyclic AMP in the cell. A high level of cystolic Ca2+ also decreases absorption. Osmolytes which are impermeable hold water in the intestinal umen. CYclic GMP in the intestinal cells is increased by certain toxins and inhibits electrolyte and water reabsorption.

33

All of the following statements related to electrolytes and water reabsorption are correct except for:


  A high lumen pH stimulates sodium and water absorption.

  Amino acids stimulate Na+ absorption.

  Glucose stimulates Na+ and water absorption.

  Increased by prostaglandin.

  Decreased by osmolytes in the intestine.


A high pH increases Na+-H+ counter-transport sincether eis abigger gradient for H+. Amino acids and glucose are co-transported with the Na+. Impermeable osmolytes hold water in the intestine. Prostaglandins do not increase reabsorption and may inhibit reabsorption.

34

Diarrhoea may result from all of the following except for:


  Decreased levels of cyclic AMP in intestinal mucosal cells.

  Increased osmolytes in the intestine.

  Increased cyclic GMP in intestinal mucosal cells.

  Decreased transit time.

  Excess histamine.


A low level of cyclic AMP inreases the absorption of electrolytes and water. A high level of cyclic AMP inhibits reabsorption and cases diarrhoea. Diarrhoea may also result from adecreased colonic transit time. In addition decreased water absorption produced by various toxins increasing cyclic GMP or increased lumen osmolytes holding water in the intestine may case diarrhoea. Histamine in excess may stimulate secretion of acid and fluid by the stomach to such an extent that diarrhoea results. A high cystolic calcium, a high cel cyclic AMP or high cell cyclic GMP cause diarrhoea, and toxins act by one or the other of these modalites to decrease salt and water absorption.

35

Diarrhoea may result from all the following except for:


  Increased secretion of Cl- by crypt cells.

  Increased cyclic AMP in intestinal mucosal cells.

  Excess somatostatin.

  Cholera toxin.

  E. coli toxin.


Cholera toxin increases cell cyclic AMP which inhibts water and electrolyte absorption. E. coli toxin increases cyclic GMP which inhibits water an electrolyte absorption. This will cause diarrhoea. If ther is inreased secretoin of Cl- by the crypt cells this may overload the colon and cause diarrhoea. Somatostatin will inhibit these actions in part and does not case diarrohea.

36

Trypsinogen is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Trypsinogen is secreted by the pancreas.

37

Activation of trypsinogen is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Trypsinogen is activated by enterkinase which is present in the duodenum.

38

Na+-glucose co-transport is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Na+-glucose co-trasport occurs predominantly in the small intestine.

39

Fatty acid absorption is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Fatty acid absorption ocurs in teh small intestine.

40

Fat-soluble vitamin absorption is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Fat-soluble vitamins are absorbed together with bile acids in the terminal ileum.

41

The most active muscle contraction occurs in the:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Of the structures listed, the most active muscle contraction is in the stomach, particularly the antrum and the body.

42

Bile acid absorption is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Bile acids are absorbed in the ileum and unergo enterohepatic circulation.

43

Iron absorption is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Iron is absorbed in the duodenum where it is in the ferrous form owing to the low pH.

44

Vitamin B12 absorption is most closely associated with:


  Stomach

  Duodenum

  Pancreas

  Small intestine (jejunum)

  Ileum


Vitamin B12 is absorbed in the terminal ileum provided intrinsic factor secreted by the parietal cells of the stomach is present.

45

Diarrhoea may result rom all of the following except for:


  Excess sodium chlord in the diet.

  Decreased transit time.

  Pancreatic lipase deficiency.

  Excess histamine.

  Excess serotonin.


Excess NACl in th diet does not cause diarrhoea as it is all reabsorbed by the jejunum. Thus it does not give an increased osmolyte or osmotic loadto the colon and does not cause diarrhoea. istamine and serotonin will increase cystolic Ca2+ and case diarrhoea. Absence of pancreatic lipase means that fat is not digested and causes diarrhoea (more correctly steatorrhoea).

46

Gastrin secretion is most closely associated with:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


Most gastrin is secreted fromt he antrum of the stomach. The duodenum and the pancrease (delta cells) also contain some gastrin.

47

Cholecystokinin release is most closely associated with:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


Cholecystokinin is released from the duodenum.

48

Motilin release is most closely associated with:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


Motilin, which controls motility of the stomach and the intestine, is released from the duodenum.

49

Somatostatin secretion is most closely associated with:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


Somatostatin is released from the antrum when the pH is < 3.5.

50

Contraction caused by a fatty meal is most closely associated with:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


The gall bladder contracts after a fatty meal owing to cholecystokinin release when fat enters the duodenum.

51

The thickest muscle is found in the:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancrease.


The antral (and pyloric)muscle are thick and a good contractile force.

52

Islet cells are found in the:


  Body of stomach

  Antrum of stomach

  Duodenum

  Gall bladder.

  Pancreas.


Islet cells that have three cell types (α, β, Δ) (insulin, glucagon, gastrin) are in the pancreas. Somatostatin is also present in the Δ cells.