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Question 1
Correct
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Regarding antimuscarinic antispasmodics, which of the following statements is CORRECT:
Your Answer: They are contraindicated in paralytic ileus.
Explanation:Antimuscarinics are contraindicated in paralytic ileus. Antimuscarinics reduce intestinal motility by blocking muscarinic acetylcholine receptors and relaxing smooth muscle. Hyoscine butylbromide is advocated as a gastrointestinal antispasmodic, but it is poorly absorbed and thus has limited clinical utility. Antimuscarinics cause a reduction in bronchial secretions (they can be used to this effect in palliative patients). Antispasmodics are occasionally of value in treating abdominal cramp associated with diarrhoea but they should not be used for primary treatment. Antispasmodics should be avoided in young children with gastroenteritis because they are rarely effective and have troublesome side effects.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 2
Correct
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By what mechanism does Vibrio cholerae causes diarrhoea?
Your Answer: Increases Cl- secretory channels in crypt cells
Explanation:Cholera is a severe diarrheal illness caused by the Vibrio cholerae bacteria infecting the bowel. Ingesting cholera-infected food or drink is the a way to contract the disease. In the intestinal crypt cells, the toxigenic bacterium Vibrio cholera activates adenylate cyclase and raises cyclic adenosine monophosphate (cAMP).
cAMP stimulates the Cl-secretory channels in crypt cells, resulting in the secretion of chloride with sodium ions and water. The toxin it produces causes the body to secrete massive amounts of water, resulting in diarrhoea and significant fluid and electrolyte loss.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 3
Correct
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Regarding antacids, which of the following statements is CORRECT:
Your Answer: Antacids are contraindicated in hypophosphataemia.
Explanation:Antacids are contraindicated in hypophosphataemia. Liquid preparations are more effective than tablet preparations. Magnesium-containing antacids tend to be laxative whereas aluminium-containing antacids tend to be constipating. Antacids are best taken when symptoms occur or are expected, usually between meals and at bedtime. Antacids should preferably not be taken at the same time as other drugs since they may impair absorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 4
Correct
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Which of the following is required for vitamin B12 absorption:
Your Answer: Intrinsic factor
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 5
Correct
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Which of the following statements about vitamin B12 absorption is TRUE:
Your Answer: On ingestion, vitamin B12 is bound to R protein which protects it from digestion in the stomach.
Explanation:The substance intrinsic factor,
essential for absorption of vitamin B12 in the ileum, is
secreted by the parietal cells along with the secretion of
hydrochloric acid. When the acid-producing parietal
cells of the stomach are destroyed, which frequently
occurs in chronic gastritis, the person develops not only
achlorhydria (lack of stomach acid secretion) but often
also pernicious anaemia because of failure of maturation
of the red blood cells in the absence of vitamin B12 stimulation of the bone marrow. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 6
Correct
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Question 7
Correct
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A 29 year old patient with known inflammatory bowel disease presents to ED with surgical complications following his recent ileocaecal resection. Removal of the terminal ileum may result in the malabsorption of which of the following:
Your Answer: Vitamin B12
Explanation:On ingestion, vitamin B12 is bound to R protein found in saliva and gastric secretions, which protects it from digestion in the stomach. Intrinsic factor is secreted by gastric parietal cells. Receptors for the IF-B12 complex are present in the membrane of epithelial cells of the terminal ileum, which bind the complex and allow uptake of vitamin B12 across the apical membrane by endocytosis. Vitamin B12 is then transported across the basal membrane into the portal blood where it is bound to transcobalamin II and processed by the liver. In pernicious anaemia, there are autoantibodies against gastric parietal cells and intrinsic factor, resulting in vitamin B12 deficiency anaemia.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 8
Correct
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During swallowing, which of the following structures primarily closes the tracheal opening:
Your Answer: Epiglottis
Explanation:The vocal cords of the larynx are strongly
approximated, and the larynx is pulled upward
and anteriorly by the neck muscles. These actions,
combined with the presence of ligaments that
prevent upward movement of the epiglottis, cause
the epiglottis to swing back over the opening
of the larynx. All these effects acting together
prevent the passage of food into the nose and
trachea. Most essential is the tight approximation
of the vocal cords, but the epiglottis helps to
prevent food from ever getting as far as the vocal
cords. Destruction of the vocal cords or of the
muscles that approximate them can cause
strangulation. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 9
Correct
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Intrinsic factor is vital for gastrointestinal absorption of which of the following:
Your Answer: Vitamin B12
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 10
Incorrect
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Gastrin release from antral G-cells is stimulated by all but which one of the following:
Your Answer: Small peptides and amino acids in chyme
Correct Answer: Secretin
Explanation:Gastrin secretion is stimulated by:
The presence of small peptides and amino acids in chyme
Gastric distension
Vagal stimulation directly via acetylcholine and indirectly via gastrin-releasing peptide (GRP)
Raised gastric pH -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 11
Incorrect
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Surface area of the absorptive surface in the small intestine is increased by all but which of the following:
Your Answer: Villi
Correct Answer: Teniae coli
Explanation:Factors increasing the surface area include:The small intestine is very long – about 5 m in length.The inner wall of the small intestine is covered by numerous folds of mucous membrane called plicae circulares.The lining of the small intestine is folded into many finger-like projections called villi.The surface of the villi is covered with a layer of epithelial cells which, in turn, have many small projections called microvilli that project towards the lumen of the intestine (forming the brush border).
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 12
Correct
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Gastrin primarily acts to perform which of the following functions:
Your Answer: Stimulate gastric acid secretion
Explanation:Gastrin primarily acts to stimulate acid secretion from parietal cells (both directly and indirectly by stimulating release of histamine from ECL cells).
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 13
Correct
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Pancreatic acinar digestive enzyme secretion is mainly stimulated by which of the following hormones:
Your Answer: Cholecystokinin
Explanation:Exocrine pancreatic secretion is controlled by:
Parasympathetic stimulation which enhances secretion of both the enzyme and aqueous components
Sympathetic stimulation which inhibits pancreatic secretion
Secretin which stimulates secretion of the alkaline-rich fluid from ductal cells
Cholecystokinin which stimulates secretion of the enzyme-rich fluid from acinar cells
Somatostatin which inhibits secretion from both acinar and ductal cells
Gastrin which stimulates pancreatic acinar cells to secrete digestive enzymes -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 14
Correct
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Intrinsic factor is secreted by which of the following cell types in the stomach:
Your Answer: Parietal cells
Explanation:Intrinsic factor is essential for the absorption of the small amounts of vitamin B12 normally present in the diet from the terminal ileum. The parietal cells of the stomach produce intrinsic factor, and following a gastrectomy, the absorption of vitamin B12 will be markedly reduced, and a deficiency state will exist.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 15
Incorrect
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Regarding water and electrolyte absorption in the small intestine, which of the following statements is INCORRECT:
Your Answer: Water follows osmotic gradients set up by the transport of ions, primarily mediated by the sodium pump.
Correct Answer: Na+ enters the cell across the apical membrane against its concentration gradient by both membrane channels and transporter protein mechanisms.
Explanation:As the contents of the intestine are isotonic with body fluids and mostly have the same concentration of the major electrolytes, their absorption is active. Water cannot be moved directly, but follows osmotic gradients set up by the transport of ions, primarily mediated by the sodium pump.Na+/K+ ATPase located on the basolateral membrane of the epithelial cells pumps three Na+ ions from the cell in exchange for two K+ ions, against their respective concentration gradients. This leads to a low intracellular concentration of Na+ and a high intracellular concentration of K+. The low intracellular concentration of Na+ ensures a movement of Na+ from the intestinal contents into the cell down its concentration gradient by both membrane channels and transporter protein mechanisms. Na+ is then rapidly pumped again by the basolateral sodium pump. K+ leaves the cell across the basolateral membrane down its concentration gradient linked to an outward movement of Cl- against its concentration gradient (Cl- having entered the cell across the luminal membrane down its concentration gradient).
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 16
Incorrect
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Gastrin is secreted by which of the following cell types in the stomach:
Your Answer: Parietal cells
Correct Answer: G-cells
Explanation:Gastrin is secreted by antral G-cells and acts on cholecystokinin B (CCKB) receptors.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 17
Incorrect
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Which of the following is NOT a function of the commensal intestinal bacterial flora:
Your Answer: Convert primary bile acids to secondary bile acids
Correct Answer: Breakdown of haem into bilirubin
Explanation:Commensal intestinal bacterial flora have a role in:Keeping pathogenic bacteria at bay by competing for space and nutrientConverting conjugated bilirubin to urobilinogen (some of which is reabsorbed and excreted in urine) and stercobilinogen which is excreted in the faecesThe synthesis of vitamins K, B12, thiamine and riboflavinThe breakdown of primary bile acids to secondary bile acidsThe breakdown of cholesterol, some food additives and drugs
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 18
Correct
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Gastric emptying is increased by all of the following EXCEPT for:
Your Answer: Secretin
Explanation:Gastric emptying is increased by:
Distension of the pyloric antrum
A fall in the pH of chyme in the stomach
Parasympathetic stimulation (via vagus)
Gastrin
The hormones secretin, cholecystokinin and gastric inhibitory polypeptide (GIP) inhibit gastric emptying. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 19
Correct
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A 33 year old female patient presents to emergency room with some symptoms that she thinks might be due to a drug that she has recently started. She was started on hyoscine butyl bromide for symptomatic relief of irritable bowel syndrome. The least likely expected side effect of this drug in this patient is:
Your Answer: Diarrhoea
Explanation:One of the commonest antispasmodic medications that is used is hyoscine butylbromide. It is an antimuscarinic and typical side effects of this class of drugs include:
– dilation of pupils with loss of accommodation (cycloplegia)
-photophobia resulting in blurred vision (Blind as a bat)
-dry mouth, eyes and skin (Dry as a bone),
-elevated temperature (Hot as a hare)
-skin flushing (Red as a beet)
-confusion or agitation particularly in the elderly (Mad as a hatter)
-reduced bronchial secretions
-transient bradycardia followed by tachycardia, palpitation and arrhythmias
-urinary retention and/or constipation -
This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 20
Correct
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On which of the following types of receptors does loperamide act?
Your Answer: Opioid receptors
Explanation:Loperamide inhibits acetylcholine release from the myenteric plexus acts by action on opioid mu-receptors, and this then reduces bowel motility. The intestinal transit time is increased, thereby facilitating water reabsorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 21
Correct
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Which of the following cell types in the stomach secretes histamine?
Your Answer: Enterochromaffin-like cells
Explanation:The parietal cells operate in close association with another type of cell called enterochromaffin-like cells (ECL cells), the primary function of which is to secrete histamine. The ECL cells lie in the deep recesses of the oxyntic glands and therefore release histamine indirect contact with the parietal cells of the glands.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 22
Incorrect
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Pancreatic ductal alkaline fluid secretion is mainly stimulated by which of the following hormones:
Your Answer: Cholecystokinin
Correct Answer: Secretin
Explanation:Pancreatic exocrine secretion is controlled by:
Parasympathetic stimulation which enhances secretion of both the enzyme and aqueous components
Sympathetic stimulation which inhibits pancreatic secretion
Secretin which stimulates secretion of the alkaline-rich fluid from ductal cells
Cholecystokinin which stimulates secretion of the enzyme-rich fluid from acinar cellsSomatostatin which inhibits secretion from both acinar and ductal cells
Gastrin which stimulates pancreatic acinar cells to secrete digestive enzymes -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 23
Correct
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Regarding carbohydrate, which of the following statements is INCORRECT:
Your Answer: Most dietary carbohydrate is in the form of disaccharides.
Explanation:Carbohydrates are the main energy source of most diets. They provide 17 kJ (4 kcal) of energy per gram. Most dietary carbohydrate is in the form of polysaccharides. The principal ingested polysaccharides are starch which is derived from plant sources and glycogen which is derived from animal sources. Dietary fibre consists of indigestible carbohydrate (found in plant foods) such as cellulose, lignin and pectin.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 24
Incorrect
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Regarding protein digestion, which of the following statements is CORRECT:
Your Answer: The pancreatic proteases, trypsin and chymotrypsin, hydrolyse polypeptides to small peptides and amino acids.
Correct Answer: Oligopeptides are broken down into small peptides and amino acids by pancreatic carboxypeptidases and aminopeptidases located on the brush border.
Explanation:Digestion of dietary protein begins in the stomach where pepsin hydrolyses protein to polypeptides, and continues in the duodenum where pancreatic proteases (trypsin and chymotrypsin) continue the process of hydrolysis forming oligopeptides. These are further broken down into small peptides and amino acids by pancreatic carboxypeptidases and aminopeptidases located on luminal membrane epithelial cells. Free amino acids are absorbed across the apical membrane by secondary active transport coupled with Na+transport into the cell. Amino acids cross the basal membrane into the capillaries by facilitated diffusion.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 25
Incorrect
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Gastric emptying is inhibited by all of the following EXCEPT for:
Your Answer: Cholecystokinin
Correct Answer: Parasympathetic stimulation
Explanation:Gastric emptying is decreased by:
Enterogastric inhibitory reflexes stimulated by – Distension of the duodenum, The presence of fats in the duodenum (by stimulating release of cholecystokinin), A fall in the pH of chyme in the duodenum, An increase in the osmolality of chyme in the duodenum, Irritation of the mucosal lining of the duodenum, Hormones: Cholecystokinin, Secretin -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 26
Correct
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Which of the following vitamins is not paired correctly with its deficiency syndrome:
Your Answer: Vitamin B12 - Wernicke-Korsakoff syndrome
Explanation:Clinical Effects of vitamin deficiency include:
Vitamin C – Scurvy
Thiamine (Vitamin B1) – Beriberi/Wernicke-Korsakoff syndrome
Vitamin B12 – Megaloblastic anaemia/Subacute combined degeneration of spinal cord
Folate – Megaloblastic anaemia
Vitamin D – Osteomalacia/Rickets
Vitamin K – Defective clotting
Vitamin A – Blindness -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 27
Incorrect
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Gastrin release from antral G-cells is inhibited by all but which one of the following:
Your Answer: Somatostatin
Correct Answer: Vagal stimulation
Explanation:Gastrin secretion is inhibited by:
Low gastric pH (negative feedback mechanism)
Somatostatin
Secretin
Gastric inhibitory polypeptide (GIP)
Cholecystokinin -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 28
Correct
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Which of the following lifestyle changes is not likely to improve symptoms of gastro-oesophageal reflux disease (GORD):
Your Answer: Lowering the head of the bed
Explanation:The following approaches have some benefit in adult patients with reflux:
Weight loss or weight management for individuals who are overweight
Head of bed elevation is important for individuals with nocturnal or laryngeal symptoms, but its value for other situations is unclear.
The following lifestyle approaches also are used frequently. There is some evidence that these lifestyle changes improve laboratory measures of reflux (such as lower oesophageal sphincter pressure).
Dietary modification – A practical approach is to avoid a core group of reflux-inducing foods, including chocolate, peppermint, and alcohol, which may reduce lower oesophageal sphincter pressure. Acidic beverages, including colas with caffeine and orange juice also may exacerbate symptoms.
Avoiding the supine position soon after eating.
Promotion of salivation by either chewing gum or using oral lozenges. Salivation neutralizes refluxed acid, thereby increasing the rate of oesophageal acid clearance.
Avoidance of tobacco (including passive exposure to tobacco smoke) and alcohol. Nicotine and alcohol reduce lower oesophageal sphincter pressure, and smoking also diminishes salivation. -
This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 29
Correct
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Regarding fat digestion, which of the following statements is CORRECT:
Your Answer: Chylomicrons are exocytosed from enterocytes to enter lacteals and thus the lymphatic system.
Explanation:Dietary fat is chiefly composed of triglycerides (esters of free fatty acids and glycerol which may be saturated or unsaturated). The essential fatty acids are linoleic acid and alpha-linoleic acid, which cannot be manufactured in the body. Dietary fat provides 37 kJ (9 kcal) of energy per gram. Fats are digested almost entirely in the small intestine and are only released from the stomach into the duodenum at the rate at which they can be digested.
Pancreatic lipase is the most significant enzyme for fat digestion. In the duodenum fat is emulsified by bile acids, a process where larger lipid droplets are broken down into much smaller droplets providing a greater surface area for enzymatic digestion. Micelles are arranged so that hydrophobic lipid molecules lie in the centre, surrounded by bile acids arranged such the outer region is hydrophilic. Dietary and synthesised lipids are incorporated into chylomicrons in the Golgi body, which are exocytosed from the basolateral membrane to enter lacteals and thus the lymphatic system. -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 30
Incorrect
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Regarding fat digestion, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Chylomicrons consist of a cholesterol and triglyceride core with a phospholipid coat studded with apolipoproteins.
Explanation:Dietary fat is chiefly composed of triglycerides. In the duodenum fat is emulsified by bile acids, a process where larger lipid droplets are broken down into much smaller droplets providing a greater surface area for enzymatic digestion. Once inside the epithelial cell, lipid is taken into the smooth endoplasmic reticulum where much of it is re esterified. Dietary and synthesised lipids are then incorporated into chylomicrons in the Golgi body, which are exocytosed from the basolateral membrane to enter lacteals. Chylomicrons consist mainly of triglyceride with small amounts of cholesterol and cholesteryl esters in the centre with a phospholipid coat studded with apolipoproteins. Fat-soluble are absorbed into enterocytes from micelles by simple diffusion together with the products of fat digestion.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
