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Question 1
Incorrect
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Which of the following enzymes is mainly responsible for the hydrolysis of polysaccharide 1:6a linkages?
Your Answer: Sucrase
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 2
Incorrect
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The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your Answer: CN XI
Correct Answer: CN IX
Explanation:Parasympathetic presynaptic nerve fibers from the glossopharyngeal nerve (CN IX) synapse in the otic ganglion and the postsynaptic parasympathetic nerve fibers pass to the parotid gland via the auriculotemporal nerve.
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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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Normally the portal venous pressure is about:
Your Answer: None of the above
Correct Answer: 5mmhg
Explanation:Under normal physiological conditions, the pressure in the portal vein, which carries blood from the gastrointestinal tract and spleen to the liver, typically ranges around 5-10 mmHg. Pressures significantly higher than this range can indicate portal hypertension, which can be associated with liver diseases such as cirrhosis.
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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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How are the long chain fatty acids (more than 10 to 12 carbon atoms) absorbed?
Your Answer: Re-esterified to triglycerides and enter capillaries as low density lipoproteins
Correct 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 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 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 7
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: Noradrenergic nerve stimulation of the hepatic artery
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 8
Incorrect
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Which of the following is responsible for transporting both glucose and fructose into the interstitium?
Your Answer: GLUT 5
Correct 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 9
Incorrect
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The lamina propria contains all of the following except:
Your Answer: Lymphocytes
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 10
Incorrect
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The cells that secrete pepsinogen and gastric lipase are found in which part of the stomach?
Your Answer: Throughout the stomach
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 11
Incorrect
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The oligosaccharidases responsible for further digestion of starch after breakdown by the above mentioned enzymes is located where?
Your Answer: Gastric folds and secretions
Correct Answer: Brush border of small intestine
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 known as the brush border. Thus, the enzymes embedded in those microvilli are referred to as brush border enzymes.
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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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Role of bile salts in digestion of fats include
Your Answer: Facilitate diffusion and active transport
Correct Answer: Reduce surface tension, emulsification and transportation
Explanation:Bile acts to some extent as a surfactant reducing surface tension, helping to emulsify the lipids in food. Bile salt anions are hydrophilic on one side and hydrophobic on the other side; consequently, they tend to aggregate around droplets of lipids (triglycerides and phospholipids) to form micelles, with the hydrophobic sides towards the fat and hydrophilic sides facing outwards. The hydrophilic sides are negatively charged, and this charge prevents fat droplets coated with bile from re-aggregating into larger fat particles.
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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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Where in the course of the gastrointestinal tract does the first significant digestion of fat begin in a normal human being?
Your Answer: Mouth
Correct Answer: Duodenum
Explanation:The enzyme lipase which is responsible for digestion of fat is secreted by the exocrine pancreas in the 2nd part of the duodenum at the point where the pancreatic duct opens. It opens together with the common bile duct which contains bile that emulsify fat aiding in digestion. The oesophagus, stomach and mouth do not contain enzymes related to fat digestion.
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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 sympathetic supply to the stomach comes from the:
Your Answer: Celiac plexus
Explanation:The vagus nerve supplies the stomach and up to proximal two-thirds of the large intestine and has parasympathetic stimulation. The sympathetic chain which begins at the level of he 1st thoracic vertebra and extends up to 3rd lumbar vertebra gives off the celiac plexus which mainly supplies the stomach. The mesenteric plexus mainly supplies the small intestine and is located below the celiac plexus in the sympathetic chain.
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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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Where does protein digestion begin?
Your Answer: Jejunum
Correct Answer: Stomach
Explanation:Digestion typically begins in the stomach when pepsinogen is converted to pepsin by the action of hydrochloric acid, and continued by trypsin and chymotrypsin in the small intestine.
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This question is part of the following fields:
- Gastrointestinal
- Medicine
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Question 16
Correct
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In addition to its role in digestion and absorption of fats, bile:
Your 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 17
Incorrect
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Absorption of protein antigens i.e. bacterial and viral proteins takes place in the:
Your Answer: Islets of Langerhans
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 18
Incorrect
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Which of the following proteins are NOT synthesized in the liver?
Your Answer: Acute-phase proteins
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 19
Incorrect
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Which glucose transporter is responsible for the uptake of dietary glucose from the gut?
Your Answer: GLUT1 45k
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 20
Correct
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Which of the following factors is not completely produced in the liver?
Your 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 21
Correct
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Which area in the GIT lacks Basic Electrical Rhythm?
Your Answer: Oesophagus
Explanation:The basal or basic electrical rhythm acts to coordinate peristalsis and are initiated in the interstitial cells of Cajal, specialized pacemaker cells located in the wall of the stomach, below the oesophagus.
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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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VIP, GIP and somatostatin play an inhibitory role in gastric acid secretion by inactivating?
Your Answer: Parietal cells
Correct 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 23
Incorrect
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One function of the liver is synthesis and storage of protein. Which of the following will result in hypoalbuminemia?
Your Answer: Hypercatabolic states
Correct Answer: All of the above
Explanation:Both trauma and sepsis cause an acute inflammatory response causing plasma leakage of albumin. Nephropathy causes leakage of albumin from glomeruli and excretion of albumin in urine known as albuminuria. A hypercatabolic state is characterized by increased circulating catabolic hormones and increase break down of proteins.
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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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Which two ducts form the ampulla of Vater?
Your Answer: The pancreatic duct of Wirsung and the duct of Santorini
Correct Answer: The common bile duct and the pancreatic duct of Wirsung
Explanation:The ampulla of Vater, also known as the hepatopancreatic ampulla or the hepatopancreatic duct, is formed by the union of the pancreatic duct and the common bile duct. The ampulla is specifically located at the major duodenal papilla.
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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 intestinal cells play a major role in secretory immunity?
Your Answer: Mucous cells
Correct Answer: M cells
Explanation:M cells are specialized epithelial cells of the MALT or mucosa-associated lymphoid tissues. They transport antigens from the intestinal lumen to cells of the immune system, thereby initiating an immune response. T and B cells are lymphocytes found in blood. Mucous cells secrete mucous and can be considered as a part of innate immunity. Chief cells in the gastric mucosa secret pepsin.
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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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The pyloric sphincter is largely made up of thickening of
Your Answer: The circular muscle layer
Explanation:The pyloric sphincter, or valve, is a strong ring of smooth muscle (circular muscle layer) at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum. It receives sympathetic innervation from the celiac ganglion.
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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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Which enzyme is responsible for the formation of the active endopeptidases from their inactive precursors?
Your Answer: Pepsin
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 29
Incorrect
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Which of the following happens when anterograde neurons are stimulated?
Your Answer: Smooth muscle contraction ahead of the stimulus
Correct 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 30
Incorrect
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The enzyme located on the brush border of the small intestine activating the proteolytic enzymes for further digestion of proteins is called?
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 the 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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