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Question 1
Correct
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The pressure in the portal circulation is normally adjusted in the:
Your Answer: Sinusoids
Explanation:The pressure in the portal circulation depends on the pressure of the hepatic sinusoids mainly because the direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids.
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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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All of the following constitute small intestinal brush border enzymes except:
Your Answer: Sucrase
Correct Answer: Alpha-amylase
Explanation:The final step in digestion of carbohydrates, which is conversion of disaccharides to absorbable monosaccharides occurs on the small intestinal epithelial cells. The enzymes responsible for this final stage of digestion are not freely found in the intestinal lumen, but they are found as integral membrane proteins in the plasma membrane of the epithelial cell. The apical plasma membrane of the intestinal epithelial cell has numerous microvilli which extend from the cell known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes. All these enzymes except alfa amylase are brush border enzymes. Alfa amylase is secreted by pancreatic acinar cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 3
Incorrect
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H+ ions used in the production of acid by parietal cells is produced with the help of which enzyme?
Your Answer:
Correct Answer: Carbonic anhydrase ii
Explanation:Carbonic anhydrase enzyme catalyses the rapid interconversion of carbon dioxide and water to bicarbonate and protons (or vice versa). This is a reversible reaction that takes place in the gastric parietal cells.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 4
Incorrect
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Protein digestion starts in the stomach by which enzyme?
Your Answer:
Correct Answer: Pepsin
Explanation:Pepsinogen is the inactive form of pepsin which is secreted by gastric chief cells and is converted to pepsin, in the presence of gastric HCL. Pepsin is a peptidase that breaks down proteins into smaller peptides.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 5
Incorrect
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There is normally an inverse relationship between the hepatic artery and portal venous blood flow. This is maintained by:
Your Answer:
Correct Answer: All of the options are correct
Explanation:There is an inverse relationship between the blood flow of the hepatic artery and portal vein. It is maintained by several factors such as chemicals like adenosine, neurohumoral substances, the morphology of the hepatic portal system (especially the ability of hepatic sinusoids to collapse) and myogenic control which causes vasoconstriction or vasodilation.
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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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Question 7
Incorrect
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Regarding carbohydrates absorption;
Your Answer:
Correct Answer: Intestinal absorption of sugars is inhibited by the drug phlorizin
Explanation:The main role of insulin is in the uptake of glucose from blood to tissues where it is metabolised. Glycose transporters in the intestines do not depend on the action of insulin. Phlorizin is a competitive inhibitor of SGLT1 and SGLT2 because it competes with glucose for the binding site, reducing intestinal and renal glucose transport.
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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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Intrinsic Factor is released by,
Your Answer:
Correct 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 9
Incorrect
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Which of the following is not secreted by cells in the antrum of the stomach?
Your Answer:
Correct Answer: Hydrochloric acid
Explanation:Cells in the body of the stomach secrete mucus, HCl and pepsinogen. Cells in the antrum secrete pepsinogen, gastrin and mucus.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 10
Incorrect
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Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer:
Correct Answer: Microfold cells (m cells) of the intestine
Explanation:M cells are specialized epithelial cells. They have a high capacity of transcytosis of microorganisms and macromolecules. They rapidly uptake antigens and present them to immune cells associated with the gut. In contrast to absorptive enterocytes, M cells do not exert direct defence mechanisms to antigens and pathogens in the intestinal cavity. Crypts of Lieberkühn are located mainly in the small intestine and large intestine and the main function is to replenish epithelial cells and to secrete intestinal enzymatic juice as well as mucous. Brunner’s glands empty into intestinal glands and their main function is to secrete mucin and to form a protective mucus layer on the duodenal epithelial cells to protect it from acidic chyme coming from the stomach. Islets of Langerhans are located in the pancreas and secrets insulin mainly. Mucosa associated lymphoid tissue plays a role in inducing immune response after presentation of antigens.
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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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The alpha amylases hydrolyse which linkages in the ingested polysaccharides?
Your Answer:
Correct Answer: 1:4α linkages
Explanation:Alfa amylase hydrolyses the α (1-4) glyosidic bonds in amylose and amylopectin and leave primarily maltose.
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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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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer:
Correct Answer: Body and fundus
Explanation:Stomach can be divided in to different regions. Cardia, fundus, body, antrum and pylorus from proximal end to distal end respectively. Cells that secret the inactive form of pepsin or pepsinogen are chief cells and are abundant in the body (corpus) and the fundus region of the stomach.
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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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Which of the following proteins are NOT synthesized in the liver?
Your Answer:
Correct Answer: Steroid
Explanation:Human steroidogenesis occurs in a number of locations:- Corticosteroids are produced in the adrenal cortex.- Oestrogen and progesterone are made primarily in the ovary and the placenta during pregnancy, and testosterone in the testes.- Testosterone is also converted to oestrogen to regulate the supply of each in females and males.- Some neurons and glia in the central nervous system (CNS) express the enzymes required for the local synthesis of pregnant neurosteroids, de novo or from peripheral sources.
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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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Glucose absorption in the small intestine is coupled with which of the following electrolytes?
Your Answer:
Correct Answer: Na
Explanation:Sodium-glucose linked transporter are family of proteins of different types. SGLT1 transporter is found in the intestinal mucosa of the small intestine and absorbs glucose via cotransport of Na+ ions.
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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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In addition to its role in digestion and absorption of fats, bile:
Your Answer:
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 16
Incorrect
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Which of the following forms an important constituent of the brush border on the microvilli of the intestinal epithelium?
Your Answer:
Correct Answer: Hydrolases
Explanation:There are certain enzymes which are part of the brush border cells including hydrolases also known as the brush border hydrolases. They perform the final step in digestion of certain nutrients.
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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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Which of the following is the most common route of hepatitis B transmission worldwide?
Your Answer:
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 18
Incorrect
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Which of the following acts on the pancreas to secrete pancreatic juice that is rich in enzymes?
Your Answer:
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 19
Incorrect
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Which of the following substances inhibits pancreatic secretion?
Your Answer:
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 20
Incorrect
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Almost all of the protein that appears in the stool is:
Your Answer:
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 21
Incorrect
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The lower oesophageal sphincter is under neural control. Which of the following causes contraction of the intrinsic sphincter?
Your Answer:
Correct 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 22
Incorrect
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Which of the following enzymes is mainly responsible for the hydrolysis of polysaccharide 1:6a linkages?
Your Answer:
Correct Answer: Isomaltase
Explanation:Isomaltase is mainly responsible for hydrolysis of 1:6α linkages. Along with maltase and sucrase, it also breaks down maltotriose and maltose.
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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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HCL is secreted by which cells in the stomach
Your Answer:
Correct 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 24
Incorrect
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The lamina propria contains all of the following except:
Your Answer:
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 25
Incorrect
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Portal vein receives its blood from all the following except:
Your Answer:
Correct Answer: Kidney
Explanation:The portal vein receives blood from the intestines via the superior and inferior mesenteric veins, from stomach via the gastric veins and from the spleen and pancreas via splenic vein. The kidney is supplied by the renal artery and drains into the renal vein into the inferior venacava.
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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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At rest, proton pumps are sequestered within the parietal cell in a series of membrane compartments known as:
Your Answer:
Correct 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
Incorrect
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Which enzyme is responsible for the formation of the active endopeptidases from their inactive precursors?
Your Answer:
Correct Answer: Enterokinase
Explanation:Enterokinase is a brush border enzyme of the duodenum that activates proteolytic enzymes for further digestion of proteins. Trypsinogen is converted to trypsin by the action of enterokinase. Trypsin and chymotrypsin are secreted by the pancreatic acinar cells and are enzymes that aid in protein digestion. Pepsin is secreted by chief cells of gastric mucosa. Procarboxydase is the inactive form of carboxypeptidase which is converted to its active form by trypsin and is secreted by pancreatic acinar cells.
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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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The blood supply to the liver is by
Your Answer:
Correct Answer: Hepatic artery and hepatic portal vein
Explanation:The liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic portal vein delivers approximately 75% of the liver’s blood supply, and carries venous blood drained from the spleen, gastrointestinal tract, and its associated organs. The hepatic arteries supply arterial blood to the liver, accounting for the remaining quarter of its blood flow.
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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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Which glucose transporter is responsible for the uptake of dietary glucose from the gut?
Your Answer:
Correct Answer: SGLT1
Explanation:SGLT 1 is responsible for the uptake of glucose via secondary active transport from the small intestine and the renal tubules.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 30
Incorrect
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The parietal cells of the stomach secrete which of the following?
Your Answer:
Correct Answer: Hydrochloric acid
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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