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Question 1
Incorrect
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Cells responsible for completely renewing the epithelium of the intestine are located:
Your Answer: At the apical surface of the villi
Correct Answer: At the base of the crypts
Explanation:Epithelial cells are renewed every 4-5 days through a process of renewal and migration. Renewal relies on proliferative cells or stem cells that reside at the crypt base of the intestinal glands. Crypts are epithelial invasions into the underlying connective tissue.
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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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The channel that coalesces the small pancreatic duct radicles before joining the common bile duct is known as the:
Your Answer: Duct of Oddi
Correct Answer: Duct of Wirsung
Explanation:The small ducts from the pancreas coalesce into a single duct known as the pancreatic duct or the duct of Wirsung. It usually joins the bile duct at the ampulla of Vater before entering the duodenum.
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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 of the following happens when anterograde neurons are stimulated?
Your Answer: Smooth muscle relaxation ahead of the stimulus
Explanation:Nitric oxide is thought to act as an anterograde neurotransmitter. Nitric oxide causes relaxation of smooth muscles ahead of the stimulus. Clinically it is used as a potent vasodilator.
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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 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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Question 5
Correct
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Di and tri peptides are absorbed via a different mechanism as amino acids, this is due to the working of which transporter?
Your Answer: PEPT 1
Explanation:GLUT and SGLT are glucose transporters. Peptides which are longer that four amino acids are not absorbed. There is abundant absorption of di and tri peptidases in the small intestine. They are absorbed into the epithelial cells of the small intestine via a transporter called PepT1 by co-transport with H+ ions.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 6
Incorrect
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Which of the following acts on the pancreas to secrete pancreatic juice that is rich in enzymes?
Your Answer: Chymotrypsin
Correct Answer: CCK
Explanation:CCK (Cholecystokinin): CCK is released by the duodenum in response to the presence of fats and proteins in the small intestine. It stimulates the pancreas to secrete enzyme-rich pancreatic juice, which aids in the digestion of fats, proteins, and carbohydrates. It also stimulates the gallbladder to contract and release bile.
Secretin: Secretin is released by the duodenum in response to acidic chyme entering from the stomach. It primarily stimulates the pancreas to release bicarbonate-rich pancreatic juice to neutralize the acid, but it does not primarily stimulate enzyme secretion.
Gastrin: Gastrin is produced by G-cells in the stomach. It stimulates gastric acid secretion by the stomach, not pancreatic enzyme secretion.
Chymotrypsin: Chymotrypsin is an enzyme produced by the pancreas. It does not act to stimulate the pancreas; rather, it is a component of the pancreatic juice that helps digest proteins.
Elastase: Elastase is also an enzyme produced by the pancreas. Like chymotrypsin, it is involved in the digestion of proteins and does not stimulate the pancreas.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 7
Incorrect
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The oesophagus is lined by
Your Answer: Simple squamous epithelium
Correct 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 8
Correct
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The following are synthesized in the liver EXCEPT?
Your Answer: Cholecystokinin
Explanation:The liver is responsible for the mainstay of protein metabolism, synthesis as well as degradation. It is also responsible for a large part of amino acid synthesis. The liver plays a role in the production of clotting factors as well as red blood cell production. Some of the proteins synthesized by the liver include coagulation factors I (fibrinogen), II (prothrombin), V, VII, VIII, IX, X, XI, XIII, as well as protein C, protein S and antithrombin. The liver is a major site of production for thrombopoietin, a glycoprotein hormone that regulates the production of platelets by the bone marrow. The liver also produces albumin, the most abundant protein in blood serum and angiotensinogen. Cholecystokinin, previously called pancreozymin, is synthesized and secreted by enteroendocrine cells in the duodenum
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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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Intrinsic Factor is released by,
Your Answer: Parietal cell
Explanation:Intrinsic factor (IF), also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells of the stomach. It is necessary for the absorption of vitamin B12 (cobalamin) later on in the small intestine.
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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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Which of the following provides the sympathetic nervous supply to the stomach?
Your Answer: Coeliac plexus
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the coeliac plexus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 11
Incorrect
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Histamine, acetylcholine and gastrin act by way of which second messengers in the release of acid by parietal cells:
Your Answer: Camp
Correct Answer: A and D
Explanation:Acetylcholine, Histamine and Gastrin receptors are located on the basolateral membrane of the parietal cell and control its activity. Stimulation of these receptors modulates the levels of protein kinases in the cell and brings about the changes from a resting to stimulated structure. Protein kinase catalyses conversion of ATP to cyclic AMP which activates the proton pump. Calcium ions increase gastric acid secretion elicited by gastrin released through a vagal mechanism, and also by a direct effect on parietal cells.
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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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Which of the following is the most common route of hepatitis B transmission worldwide?
Your Answer: Sexual transmission
Correct Answer: Perinatal transmission
Explanation:The virus is transmitted by exposure to infectious blood or body fluids. Infection around the time of birth or from contact with other people’s blood during childhood is the most frequent method by which hepatitis B is acquired in areas where the disease is common. In areas where the disease is rare, intravenous drug use and sexual intercourse are the most frequent routes of infection. Perinatal transmission is the most common and without intervention, a mother who is positive for HBsAg has a 20% risk of passing the infection to her offspring at the time of birth. This risk is as high as 90% if the mother is also positive for HBeAg.
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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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The lamina propria contains all of the following except:
Your Answer: Plasma cells
Correct 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 14
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 15
Incorrect
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Anti-gastroesophageal reflux mechanisms include the following except:
Your Answer: The phrenoesophageal ligament
Correct Answer: Peristaltic movements of the oesophagus
Explanation:The lower oesophageal sphincter contracts preventing reflux of acid into the oesophagus. The sling muscles of the stomach, the crura of the diaphragm and the phreno-oesophageal ligament all play an important role in constricting the lower portion of the oesophagus and preventing reflux. Peristaltic movements do not stop the acid reflux.
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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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Which of the following would provide relief from nausea and vomiting?
Your Answer: Opioids
Correct 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 17
Incorrect
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The ATPase of parietal cells moves:
Your Answer: H+ from the gastric lumen in exchange for a K+
Correct Answer: H+ into the gastric lumen in exchange for a k+
Explanation:ATPase of the parietal cell is also known as the proton pump, which moves H+ ions into the gastric lumen in exchange for K+ ions into the cell.
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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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Concerning protein digestion:
Your Answer: Human pepsinogens can be divided into four immunochemically distinct groups
Correct Answer: Most protein digestion occurs in the duodenum
Explanation:Human pepsinogens can be divided into two immunochemically distinct groups: Pepsinogen I (PG I) and Pepsinogen II (PGII). PG I is secreted mainly by chief cells in the fundic mucosa whereas PGII is secreted by the pyloric glands and the proximal duodenal mucosa. Maximal acid secretion correlates with PG I. Most protein digestion occurs in the duodenum/jejunum. Pepsin functions best in an acidic environment and specifically at a pH of 1.5 to 3.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 19
Incorrect
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Where does secretin work in the pancreas?
Your Answer: Acinar cells
Correct Answer: Pancreatic ducts
Explanation:Secretin, a hormone produced by the duodenal S cells in response to the stomach chyme containing high hydrogen atom concentration (high acidity), is released into the blood stream; upon return to the digestive tract, secretion decreases gastric emptying, increases secretion of the pancreatic ductal cells, as well as stimulating pancreatic acinar cells to release their zymogenic juice.
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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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How are the long chain fatty acids (more than 10 to 12 carbon atoms) absorbed?
Your Answer: Re-esterified to triglycerides and enter the lymphatics as chylomicrons
Explanation:Short and medium chain fatty acids are absorbed into the blood via intestinal capillaries and travel through the portal vein. Long chain fatty acids are not directly released into the intestinal capillaries. They are re-esterified to triglycerides and are coated with cholesterol and protein, forming chylomicrons. Chylomicrons are released in the lymphatic system.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 21
Correct
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A patient with achalasia
Your 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 22
Incorrect
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The central veins in the liver:
Your Answer: Drain into the hepatic duct
Correct Answer: Coalesce to form the hepatic vein
Explanation:The central veins coalesce to form the hepatic vein which in turn drains into the inferior vena cava. The portal vein mainly carries blood from different parts of the GIT and is not drained to the inferior vena cava.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 23
Incorrect
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Which of the following prevents auto-digestion of the stomach by gastric secretions:
Your Answer: Pepsinogen
Correct Answer: Trefoil peptides and mucus- bicarbonate layer.
Explanation:Pepsinogen is the inactive form of pepsin, a protein digesting enzyme. Bombesin is a peptide which stimulates gastrin secreting cells in the stomach increasing production of gastric acid. Ecl or enterochromaffin cells are neuroendocrine cells that aid in the production of gastric acid via the release of histamine. Oxyntic cells are also known as parietal cells and are the main cells secreting gastric hydrochloric acid (HCl). Gastric acid and pepsin are harmful agents for the gastric mucosa and can result in autodigestion. It is therefore protected by several agents including bicarbonate which neutralizes the acidity of gastric acid while Trefoil peptides are a component of gastric mucosa that form a gel like layer in the gastric epithelium protecting it from harmful agents.
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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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Cholesterol is synthesized in all of these organs EXCEPT?
Your Answer: Stomach
Explanation:The liver primarily synthesizes about 20-25% of the total daily cholesterol. Cholesterol is also synthesized to smaller extents in the adrenal glands, reproductive organs (as cholesterol is the precursor of sex hormones), skin and is also produced in the intestines.
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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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Which of the following is NOT a pancreatic enzyme?
Your Answer: Amylase
Correct Answer: Pepsinogen 1
Explanation:Pancreatic juice, composed of the secretions of both ductal and acinar cells, is made up of the following digestive enzymes:Trypsinogen, which is an inactive(zymogenic) protease that, once activated in the duodenum into trypsin, breaks down proteins at the basic amino acids. Trypsinogen is activated via the duodenal enzyme enterokinase into its active form trypsin.Colipase is a protein co-enzyme required for optimal enzyme activity of pancreatic lipase. It is secreted by the pancreas in an inactive form, procolipase, which is activated in the intestinal lumen by trypsin.Chymotrypsinogen, which is an inactive (zymogenic) protease that, once activated by duodenal enterokinase, breaks down proteins at their aromatic amino acids. Chymotrypsinogen can also be activated by trypsin.Carboxypeptidase, which is a protease that takes off the terminal amino acid group from a proteinSeveral elastases that degrade the protein elastin and some other proteins.Pancreatic lipase that degrades triglycerides into fatty acids and glycerol.Sterol esterasePhospholipaseSeveral nucleases that degrade nucleic acids, like DNase and RNase.Pancreatic amylase that breaks down starch and glycogen which are alpha-linked glucose polymers.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 26
Incorrect
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Somatostatin is responsible for?
Your Answer: Decreased smooth muscle contraction
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 27
Incorrect
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The intestine is lined by:
Your Answer: Stratified squamous epithelium
Correct Answer: Simple columnar epithelium
Explanation:In the small intestine, epithelium is simple columnar and specialised for absorption. The epithelium is arranged into villi, creating a brush border and increasing the area for absorption. The epithelium is simple columnar with microvilli.In the colon, epithelium is simple columnar and without villi. Goblet cells, which secrete mucous, are also present.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 28
Correct
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VIP, GIP and somatostatin play an inhibitory role in gastric acid secretion by inactivating?
Your Answer: G cells
Explanation:Gastrin is secreted from the G cells. VIP, GIP and somatostatin all inhibit acid production by inhibiting the G cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 29
Correct
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The end product of trehalase action on oligosaccharides is
Your 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 30
Correct
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G cells release which of the following substances
Your Answer: Gastrin
Explanation:The G cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. Gastrin-releasing peptide, as well as the presence of amino acids in the stomach, stimulates the release of gastrin from the G cells. Gastrin stimulates enterochromaffin-like cells to secrete histamine. Gastrin also targets parietal cells by increasing the amount of histamine and the direct stimulation by gastrin, causing the parietal cells to increase HCl secretion in the stomach.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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