-
Question 1
Correct
-
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
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 2
Incorrect
-
The pyloric sphincter is largely made up of thickening of
Your Answer: Both the oblique and the circular muscle layers
Correct 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 3
Incorrect
-
The end product of trehalase action on oligosaccharides is
Your Answer: A molecule of fructose 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)
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 4
Correct
-
Which of the following is NOT a component of bile?
Your Answer: Unconjugated bilirubin
Explanation:The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts (electrolytes).
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 5
Correct
-
Which of the following substances inhibits pancreatic secretion?
Your 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 6
Incorrect
-
Where does protein digestion begin?
Your Answer: Mouth
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 7
Correct
-
The pressure in the sinusoids is normally:
Your Answer: Lower than portal venous pressure
Explanation:The direction of transport of nutrients in the portal vein occurs from the portal vein to the hepatic sinusoids. Thus, he pressure of sinusoids should be lower than the pressure of he portal vein.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 8
Correct
-
Gastrin activates all of the following cells except:
Your Answer: Mucus neck cells
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 9
Correct
-
The parasympathetic innervation of the parotid salivary gland arrives from the salivary nuclei:
Your 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 10
Correct
-
Interruption of the entero-hepatic circulation causes:
Your Answer: The amount of fat in the stool to be increased
Explanation:Enterohepatic circulation refers to the circulation of biliary acids, bilirubin, drugs, or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver. One of the causes of the interruption of enterohepatic circulation is the resection of the ileum where fat is mainly absorbed. Fat malabsorption results in increased fat in stools. Pale stools and dark urine is caused by obstruction of the biliary ductal system especially the common bile duct where urobilin and stercobilin are formed.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 11
Correct
-
Where is the myenteric plexus (Auerbach’s plexus) located in the GIT?
Your Answer: Between the outer longitudinal and middle circular muscle layers.
Explanation:A part of the enteric nervous system, the myenteric plexus exists between the longitudinal and circular layers of muscularis externa in the gastrointestinal tract. It is found in the muscles of the oesophagus, stomach, and intestine.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 12
Correct
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 13
Correct
-
H+ ions used in the production of acid by parietal cells is produced with the help of which enzyme?
Your 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 14
Correct
-
Vagotomy leads to the following:
Your Answer: Irregular and chaotic peristalsis
Explanation:The Vagus nerve is primarily responsible for autonomic regulation involved in heart, lung and gastrointestinal function. The gastric branches supply the stomach. The right branch joins the celiac plexus and supplies the intestines. Vagotomy involves cutting of the vagus nerve or its branches which is a now-obsolete therapy that was performed for peptic ulcer disease. Vagotomy causes a decrease in peristalsis and a change in the emptying patterns of the stomach.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 15
Correct
-
Absorption of fructose is via:
Your Answer: Facilitated diffusion
Explanation:Dietary fructose may be ingested as a monosaccharide or as a disaccharide. Sucrose is hydrolysed by sucrase to produce equal amounts of glucose and fructose and in this form, is usually completely absorbed. Fructose is mostly absorbed in the small intestine through GLUT-5 transporter mediated facilitative diffusion. This is an energy independent process.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 16
Correct
-
What is the function of basic electrical rhythm
Your Answer: To coordinate peristalsis and other motor activity
Explanation:The basal or basic electrical rhythm (BER) or electrical control activity (ECA) determines the frequency of the contractions in the gastrointestinal (GI) tract, thus acting to coordinate peristalsis.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 17
Correct
-
Portal vein receives its blood from all the following except:
Your 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 18
Incorrect
-
Regarding carbohydrates absorption;
Your Answer: Intestinal glucose absorption requires phosphorylation
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 19
Correct
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 20
Incorrect
-
Which of the following initiates migrating motor complex
Your Answer: Acetylcholine
Correct Answer: Motilin
Explanation:Migrating motor complexes (MMC) are thought to be partially regulated by motilin, which is initiated in the stomach as a response to vagal stimulation, and does not directly depend on extrinsic nerves.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 21
Incorrect
-
The oesophagus is lined by
Your Answer: Transitional 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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 22
Incorrect
-
Role of bile salts in digestion of fats include
Your Answer: Micelle formation and absorption
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 23
Incorrect
-
Colipase is secreted in an inactive form. Its activation in the intestinal lumen is by
Your Answer: Chymotrypsin
Correct Answer: Trypsin
Explanation:The enzyme trypsin exists in pancreatic juice in the inactive form trypsinogen, it is activated by the intestinal enterokinase in intestinal juice. Trypsin can then activate other protease enzymes and catalyse the reaction pro-colipase → colipase. Colipase is necessary, along with bile salts, to enable lipase function.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 24
Incorrect
-
Regarding the anatomy of the intestine, the muscularis propria contains all of which of the following constituents?
Your Answer: Submucosa, muscularis mucosa, mesothelium
Correct Answer: Circular muscle, myenteric plexus, longitudinal muscle
Explanation:The muscularis mucosa/propria consists of the inner circular muscles and the outer longitudinal muscles. Between these muscles is the myenteric plexus.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 25
Incorrect
-
Which of the following is NOT a pancreatic enzyme?
Your Answer: Chymotrypsinogen
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 26
Incorrect
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 27
Correct
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 28
Incorrect
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 29
Incorrect
-
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.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
-
Question 30
Incorrect
-
Which of the following provides the sympathetic nervous supply to the stomach?
Your Answer: Splanchnic plexus
Correct Answer: Coeliac plexus
Explanation:Parasympathetic innervation to the stomach is from the vagus nerve and the sympathetic innervation is from the coeliac plexus.
-
This question is part of the following fields:
- Gastrointestinal
- Medicine
-
SESSION STATS - PERFORMANCE PER SPECIALTY
