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Question 1
Correct
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Which three parietal cell agonists bind at the basolateral membrane at specific receptors respectively: M3 , H2 , CCK-B, to stimulate acid secretion?
Your Answer: Acetylcholine, histamine , gastrin
Explanation:The three agonists of parietal cell secretion are gastrin, acetylcholine and histamine. Parietal cells are responsible for the secretion of HCl and intrinsic factor.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 2
Incorrect
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Which substance is produced by anterograde neurons?
Your Answer: Acetyl choline
Correct Answer: Nitric oxide
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Classically in the peripheral nervous system, it diffuses from a presynaptic nerve ending to the post synaptic effecter cell which is mainly smooth muscle cells in the gastrointestinal, respiratory and urogenital tracts.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 3
Correct
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Which inhibitor of gastric enzyme secretion is released by the presence of fat in the jejunum?
Your Answer: Peptide yy
Explanation:Peptide yy is secreted from the jejunum due to the presence of fat. It inhibits gastric acid secretion and motility.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 4
Correct
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The following can cause steatorrhea except
Your Answer: Diseases that destroy the endocrine portion of the pancreas
Explanation:Dietary fats and lipids are usually efficiently digested and over 90% absorbed. Impaired digestion or absorption can result in fatty stools. Possible causes include exocrine (not endocrine) pancreatic insufficiency, with poor digestion from lack of lipases, loss of bile salts, which reduces micelle formation, and small intestinal disease producing malabsorption. Various other causes including certain medicines that block fat absorption, or indigestible or excess oil/fat in diet.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Correct
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Acetylcholine from enteric nerve endings stimulates this pair:
Your Answer: Parietal cells and chief cells
Explanation:In the body of the stomach, the vagal postganglionic muscarinic nerves release acetylcholine(ACh) which stimulates parietal cell H+ secretion. Gastric chief cells are primarily activated by ACh. However the decrease in pH caused by activation of parietal cells further activates gastric chief cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Correct
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HCL is secreted by which cells in the stomach
Your Answer: Parietal cells
Explanation:Parietal cells are the epithelial cells that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and in the body of the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 7
Correct
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Which of the following statements correctly describes a function of the parasympathetic innervation of the GI tract.
Your Answer: Parasympathetic cholinergic activity increases the activity of intestinal smooth muscle
Explanation:The parasympathetic nerves stimulate peristalsis and relax the sphincters; they also stimulate secretion. Acetylcholine is the neurotransmitter of the parasympathetic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 8
Incorrect
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A patient with a VIPoma (VIP secreting tumour) is likely to exhibit which of the following?
Your Answer: Increased insulin secretion and hypoglycaemia
Correct Answer: Severe diarrhoea
Explanation:Vasoactive inhibitory peptide (VIP) is found in the nerves innervating the GIT. It markedly stimulates the secretion of intestinal electrolytes and also with them water. This results in secretary diarrhoea. Along with that it also relaxes intestinal smooth muscle including the sphincters, it also results in dilation of the peripheral blood vessels and along with this its also inhibits gastric acid secretions. A VIPoma will exaggerate all this.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 9
Correct
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The oesophagus is lined by
Your Answer: Stratified squamous epithelium
Explanation:The wall of the oesophagus from the lumen outwards consists of mucosa, submucosa (connective tissue), layers of muscle fibers between layers of fibrous tissue, and an outer layer of connective tissue. The mucosa is a stratified squamous epithelium of around three layers of squamous cells, which contrasts to the single layer of columnar cells of the stomach. The transition between these two types of epithelium is visible as a zig-zag line. Most of the muscle is smooth muscle although striated muscle predominates in its upper two thirds.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 10
Correct
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The lamina propria contains all of the following except:
Your Answer: Neutrophils
Explanation:The connective tissue of the lamina propria is very loose, allowing it to be very cell rich. The cell population of the lamina propria is variable and can include, for example, fibroblasts, lymphocytes, plasma cells, macrophages, eosinophilic leukocytes, and mast cells. It provides support and nutrition to the epithelium, as well as the means to bind to the underlying tissue.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 11
Correct
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Which of the following is responsible for transporting both glucose and fructose into the interstitium?
Your Answer: GLUT 2
Explanation:Absorption of glucose involves transport from the intestinal lumen, across the epithelium and into blood. The transporter that carries glucose and galactose into the enterocyte is the sodium-dependent hexose transporter, known as SGLT1. As the name indicates, this molecule transports both glucose and sodium ions into the cell. Once absorbed into the enterocyte, glucose must be exported from the cell into blood. Sodium is rapidly shuttled out in exchange for potassium by Na+/K+ ATPase pumps on the basolateral membrane, and that process maintains the electrochemical gradient across the epithelium. Glucose, galactose and fructose are transported out of the enterocyte into the interstitium and in turn into the blood through another hexose transporter (called GLUT-2) in the basolateral membrane. These monosaccharides then diffuse down a concentration gradient into capillary blood.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 12
Incorrect
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Somatostatin is responsible for?
Your Answer: Increased pancreatic secretions
Correct Answer: Decreased gastrin release
Explanation:Somatostatin is an inhibitory hormone secreted from the D cells of the Pancreatic Islets. It causes the inhibition of gastrin (decreasing stomach acid production), CCK (decreasing gallbladder motility), gastrin inhibitory peptide and secretin. Gastrin production is also inhibited by secretin, GIP, VIP, glucagon and calcitonin.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 13
Incorrect
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Emulsification of dietary lipids is brought about by
Your Answer: Cholecystokinin
Correct Answer: Bile salts
Explanation:Digestion of fats can begin in the mouth where lingual lipase breaks down some short chain lipids into diglycerides. However fats are mainly digested in the small intestine. The presence of fat in the small intestine produces hormones that stimulate the release of pancreatic lipase from the pancreas and bile from the liver which helps in the emulsification of fats for absorption of fatty acids.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 14
Incorrect
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Which of the following factors is not completely produced in the liver?
Your Answer: Factor ix
Correct Answer: Factor viii
Explanation:Factor VIII is produced in liver sinusoidal cells and endothelial cells outside of the liver throughout the body. This protein circulates in the bloodstream in an inactive form, bound to another molecule called von Willebrand factor, until an injury that damages blood vessels occurs.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 15
Correct
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The first enzyme carbohydrates encounter in the digestive tract is?
Your Answer: Amylase
Explanation:Carbohydrate digesting enzymes are known as amylase. Salivary amylase or ptyalin is the first enzyme to begin carbohydrate digestion in he oral cavity. Amylose is a component of carbohydrates and is not an enzyme. Isomaltase, maltase and sucrase are enzymes found in the small intestines that digest disaccharides like maltose and sucrose to monosaccharides.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Incorrect
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A patient with achalasia
Your Answer: None are correct
Correct Answer: Has decreased production of vasoactive intestinal polypeptide (VIP)
Explanation:Oesophageal achalasia is an oesophageal motility disorder involving the smooth muscle layer of the oesophagus and the lower oesophageal sphincter (LES). It is characterized by incomplete LES relaxation, increased LES tone, and lack of peristalsis of the oesophagus (inability of smooth muscle to move food down the oesophagus) in the absence of other explanations like cancer or fibrosis. In achalasia, there is loss of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) releasing inhibitory neurons.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 17
Correct
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The lower oesophageal sphincter is under neural control. Which of the following causes contraction of the intrinsic sphincter?
Your Answer: Acetylcholine
Explanation:The lower oesophageal sphincter (LOS) is a specific region of the oesophageal circular smooth muscle. It allows the passage of a food bolus to the stomach and prevents the reflux of gastric contents into the oesophagus. The tone of the LOS is myogenic in origin and depends on smooth muscle properties that lead to the opening of Ca2+ channels but can also be modulated by enteric motor neurons, the parasympathetic and sympathetic extrinsic nervous system and several neurohumoral substances. Nitric oxide causes LOS relaxation. Acetylcholine and tachykinins are involved in the LOS contraction.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 18
Incorrect
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Which of the following substances inhibits pancreatic secretion?
Your Answer: Cholecystokinin
Correct Answer: Pancreatic polypeptide
Explanation:Number of hormones and neurotransmitters can stimulate and inhibit pancreatic exocrine secretion. Cholecystokinin, secretin, vasoactive intestinal peptide and substance P stimulate pancreatic secretion. Pancreatic polypeptide, somatostatin inhibit pancreatic secretion.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 19
Correct
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Which of the following would provide relief from nausea and vomiting?
Your Answer: Cannabinoids
Explanation:Ondansetron, chlorpromazine and haloperidol are effective antiemetic agents. Corticosteroids, cannabinoids, and benzodiazepines, alone or in combination with 5-HT3 and D2 antagonists, are also useful in the treatment of vomiting produced by chemotherapy.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 20
Correct
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During the gastric phase, the acid secretion process is stimulated in the G cells by?
Your Answer: Vagal stimulation, distention of the stomach wall, oligopeptides in the stomach
Explanation:Before the meal enters into the stomach, the amount of secretion is limited. Swallowing of a food bolus triggers the release of gastrin. Once in the stomach, the meal physically distends the stomach activating the stretch receptors and initiating the vago vagal reflex amplifying the secretion during the gastric phase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Incorrect
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The end product of trehalase action on oligosaccharides is
Your Answer: Maltotriose and maltose
Correct Answer: Two glucose molecules
Explanation:Disaccharides are glycoside hydrolases, enzymes that break down certain types of sugars called disaccharides into simpler sugars called monosaccharides.Examples of disaccharides:Lactase (breaks down lactose into glucose and galactose)Maltase (breaks down maltose into 2 glucoses)Sucrase (breaks down sucrose into glucose and fructose)Trehalase (breaks down trehalose into 2 glucoses)
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 22
Correct
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Question 23
Incorrect
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Almost all of the protein that appears in the stool is:
Your Answer: From partially digested proteins
Correct Answer: Comes from bacteria and cellular debris
Explanation:75% of faecal weight is water. By dry weight 30% of faeces is bacteria,10-20% is fat and 2-3% proteins. Almost all proteins ingested are absorbed in the gut.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 24
Correct
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Chief cells secrete:
Your Answer: Pepsinogen and gastric lipase
Explanation:A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 25
Incorrect
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In addition to its role in digestion and absorption of fats, bile:
Your Answer: Causes jaundice in hepatitis patients
Correct Answer: Is the major excretory route for lipid-soluble waste products
Explanation:The end product of haem metabolism is bilirubin and jaundice is caused by increased bilirubin levels in the blood. Gallstones are mainly caused by cholesterol and bile pigments. Bile is the main route of excretion for lipid soluble waste products whereas urine is the main route of excretion of water soluble waste products.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 26
Correct
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At rest, proton pumps are sequestered within the parietal cell in a series of membrane compartments known as:
Your Answer: Tubulovesicles
Explanation:The gastric H, K-ATPase pump, which pumps gastric acid (HCl), in the resting state is found in cytoplasmic tubular membranes. In the stimulated state this pump moves from the tubulovesicles to the apical membrane.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 27
Correct
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Which pair is correct concerning enteroendocrine cells in the GIT mucosa and their products?
Your Answer: D cells and somatostatin
Explanation:Somatostatin, an inhibitory hormone is secreted form the D cells of the Pancreatic Islets.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 28
Incorrect
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In Hirschsprung disease which one is incorrect
Your Answer: Mostly diagnosed in infancy
Correct Answer: Due to congenital absence of myenteric and submucosal plexuses
Explanation:During normal prenatal development, cells from the neural crest migrate into the large intestine (colon) to form the networks of nerves called the myenteric plexus (Auerbach plexus) (between the smooth muscle layers of the gastrointestinal tract wall) and the submucosal plexus (Meissner plexus) (within the submucosa of the gastrointestinal tract wall). In Hirschsprung’s disease, the migration is not complete and part of the colon lacks these nerve bodies that regulate the activity of the colon. The affected segment of the colon cannot relax and pass stool through the colon, creating an obstruction.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Incorrect
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Regarding short-chain fatty acids, all the following are true except:
Your Answer: They are two-to five-carbon weak acids
Correct Answer: They are produced in the small intestine but their absorption occurs in the colon
Explanation:Short chain fatty acids (SCFAs) have carbon chains of 2-5 carbon atoms. They are produced in the large intestine and are also absorbed there. They exert a trophic effect on the colonic epithelial layer in absorption of sodium. In the absence of short chain fatty acids there is a loss of sodium and water. Transport of SCFA is coupled with sodium thus absorption leads to the accumulation in the lumen of HCO3, a rise in pH, fall in pCO2 and stimulation of Na+ and water transport. The effect on Na+ transport is thought to indicate the presence of a Na+/H+ exchange in the cell membrane.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 30
Correct
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The infoldings or spaces between the bases of the villi are known as
Your Answer: Crypts of Lieberkühn
Explanation:An intestinal gland (also crypt of Lieberkühn and intestinal crypt) is a gland found in the intestinal epithelium lining of the small intestine and large intestine (colon) between the villi.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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