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23 Cards in this Set
- Front
- Back
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GI01 [cd] [Jul98] Oesophagus at rest is:
A. Open at the top B. Open at the bottom C. Open at the top and the bottom D. Closed at the top and the bottom E. Contracted throughout its length |
ANSWER D
Oesphageal sphincter upper and lower |
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GI02 [Mar97] [Jul00] Na+ absorption in small bowel
A. Occurs by active transport B. Occurs with H+ C. Decreases with glucose ( OR: Is facilitated by glucose) B: Is by active transport at the brush border membrane C: ? passive across basolateral membrane (??diffusion) D. Occurs with Cl- through tight junctions |
ANSWER A
Actively transported at basolateral membrane via NaKATPase Secondary active co-transport at apical membrane with Na+Cl- CoTransport, Sodium channels, Sodium-glucose CoTransporter, and Sodium-AminoAcid CoTranporter. B: some absorbed while K+ or H+ are transported in the opposite direction in exchange for the Na+ ions. C: glucose is transported by a sodium co-transport mechanism, so no Na absorption means no glucose absorption. D: incorrect. E: Cl- ions are passively "dragged" along by the positive electrical charges of the Na+ |
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GI03 [d] [Jul98] [Jul99] [Jul02] After a fatty meal, most of the fat would be:
A. Absorbed in the portal circulation & transported to the liver B. Absorbed in the portal vein & transported in the hepatic artery C. Absorbed into chylomicrons in the lymphatics D. Absorbed as triglycerides into the portal vein & bypass the liver |
ANSWER C
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GI03b [Mar99] Fat digestion:
A. Bile salts are the most efficient emulsifiers B. Gastric lipase is the most important C. Pancreatic lipase in the duodenum is the most important D. Digestion takes place in micelles E. Micelles attach to enterocyte receptor |
ANSWER C
The most important enzyme for the digestion of triglycerides is pancreatic lipase. The most important emulsification of fat = lecithin (not bile salt); gastric lipase is generally unimportant, less than 10% digested |
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GI04 [Jul98] [Jul01] [Feb04]
Vitamin B12 deficiency: A. Due to decreased ingestion B. Due to decreased absorption by ileum C. Causes a deficiency in haemoglobin D. Causes a decrease in red cell production E. causes ataxia |
ANSWER C most correct
A- alcoholics are deficient in B12 due to malnutritian B- b12-IF complex absorbed in the ileum, Crohn's can get B12 deficient secondary to ileitis C- common cause of pernicious anaemia (anaemia=low Hb) D- megaloblastic anaemia, E- has caused demyelination of the corticospinal tracts. |
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GI05 [Jul98] [Jul99] [Mar03] [Jul03] [Feb04] [Jul04] Iron absorption:
A. Passive B. Binds to apoferritin in small intestine lumen C. Decreased with increased pH D. Requires acidic gastric pH E. Binds to 4 prophyrin rings in the gut F. Vitamin C is a cofactor for haem oxygenase G. Haem iron is readily absorbed in the small intestine |
ANSWER A and C
A Iron is absorbed mainly in the duodenum and jejenum, via a divalent metal transporter. It cross the apical membrane via facilitated diffusion (passive). B False - apoferritin is in mucosal cells NOT lumen C True - absorption reduced by alkali D FALSE- absorption increased by gastric acid which keeps in ferrous state (but ferric reductase in brush border can convert 3+ to 2+ so could still be absorbed) - but not required E False - when incorporated into haem in mitochondria of RBC F false - H.O. is enzyme involved in haem breakdown to biliverdin, Fe and CO. Neither Power and Kam nor Ganong state Vit c is cofactor G False : not readily. only 3-6% |
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GI06 [Jul98] [Jul00] [Feb04] Findings in iron deficiency:
A. Increased apoferritin synthesis B. Decreased transferrin saturation C. Transferrin synthesis is reduced D. Increased amounts of ferritin E. Haemosiderin is produced |
ANSWER B
see http://www.perthhaematology.com.au/IronStudies.pdf |
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GI07 [Mar99] [Feb00] [Feb04] The major route of iron excretion is:
A. Excretion of transferrin in the gut B. Shedding of intestinal mucosal cells C. Increased renal excretion D. ? |
ANSWER B
The body does NOT control the excretion of iron. The loss each day is predominantly loss of blood (and other cells) which contain iron. This loss is small but larger in females (on average) because of menstrual blood losses, as erythrocytes have a significant iron content in haemoglobin. |
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GI08 [Mar99] [Apr01] Gastric acid secretion is decreased by:
A. Vagal inhibition B. Luminal peptides & amino acids (OR: “Ingestion of protein”) C. Noradrenaline D. M1 cholinergic antagonist same efficacy at reducing gastric acid secretion E. Distension of bowel wall |
Answer A Best Answer
Vagal stimulation increase release * ACH which acts on M3 on parietal cells – direct mechanism * GRP – Gastric Release Peptide – indirect mechanism – this is released directly from nerve terminals. 1-Stimulates G cells to release Gastrin. 2-Acts directly on parietal cells Gastrin Receptors – minor mechanism. 3-Releases of histamine from Enterochromaffin cells which inturn acts on Parietal Cells – principle mechanism. Gastric Secretion is inhibited by * Somatostatin * Epidermal Growth Factor * Beta adrenergic Agonist * Enteroglucagon |
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GI09 [Jul99] [Feb00] [Apr01] Release of which ONE of the following increases the pH of duodenal contents?
A. Secretin B. Gastrin C. Intrinsic factor D. Cholecystokinin E. Gastrin releasing peptide F. Pepsin |
ANSWER A
A: Correct - Secretin is secreted from S cells in the upper intestinal mucosa, it increases secretion of bicarbonate by pancreatic duct cells and biliary tract. B: Gastrin is secreted by G cells located mainly in the gastric antrum. It stimulates the production of hydrochloric acid by parietal cells in the body of the stomach and so decreases the pH of gastric contents. It also stimulates the secretion of pepsinogen from chief (peptic) cells. C: Intrinsic factor is also secreted by parietal cells in the stomach. It binds with vitamin B12 in the stomach and prevents it from being digested before it can be absorbed in the terminal ileum. D: Cholecystokinin is released by cells in the duodenum and acts on both the pancreas and gallbladder; it simulates the release of trypsinogen, chymotrypsinogen, amylase and lipase from the pancreas; it stimulates the production of bile, the contraction of the gallbladder and the relaxation of the Sphincter of Oddi. It also mediates satiety in the CNS. CCK may potentiate the effect of secretin on increasing the duodenal pH. E: Gastrin releasing peptide also known as bombesin, is secreted from the enteric nerve of the gastric mucosa stimulating the release of gastrin from G cells. F: Pepsin is a proteolytic enzyme which is optimally active in a pH of 1.8 to 3.5; pepsinogen, the inactive precursor is secreted from gastric chief cells. |
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GI10 [Jul99] [Jul01] Speed of delivery of nutrients from stomach to small intestine:
A. CHO>fat>protein B. CHO>protein>fat C. Protein>CHO>fat D. ? E. Fat>protein>CHO |
ANSWER B
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GI11 [Jul00] [Mar03] [Jul03] Gastric emptying is slowest (OR: most prolonged) after consuming:
A. High protein meal B. High fat meal C. Alcohol D. Calcium E. Carbohydrates |
ANSWER B
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GI12 [Apr01] Chyme in duodenum is alkaline due to
A. Secretin B. ? |
Secretin acts on the pancreatic ducts to cause copious secretion of a very alkaline pancreatic juice that is rich in HCO3- and poor in enzymes. The effect on duct cells is due to an increase in intracellular cAMP. Secretin also stimulates bile secretion. CCK acts on the acinar cells to cause the release of zymogen granules and production of pancreatic juice rich in enzymes but low in volume. Its effect is mediated by phospholipase C '
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GI13 [Jul01] In the small intestine, glucose is absorbed
A. Passively B. In combination with Sodium C. By facillitated difussion D. By cotransport with Chloride E. Actively by insulin dependent uptake |
ANSWER B
Glucose is absorbed in the cells of the small intestine by two means - facilitated diffusion and by Na+ dependent facilitated transport. Na+ dependent transporters are present on the luminal side of the absorptive cells. The intracellular concentration of Na+ is kept low by the Na+/K+ ATPase at the basolateral membrane, allowing co-transport of glucose against a concentration gradient. 120g/day Facilitated diffusion is a process of diffusion, a form of passive transport facilitated by transport proteins. Facilitated diffusion is the spontaneous passage of molecules or ions across a biological membrane passing through specific transmembrane transport proteins. |
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GI14 [Jul01] After ingestion of a meal:
A. Digestion of fat and carbohydrate begins in the mouth while protein digestion begins in the stomach B. Carbohydrate in the mouth and protein in the stomach. C. Protein in mouth and fats and carbohydrate in stomach D. Most fluid and electrolytes are absorbed in the large bowel E. Composition of the food has no effect on transit time through the bowel |
ANSWER A
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GI15 [Jul01] Calcium uptake in the intestine:
A. Is passive B. Requires a carrier protein on the mucosal side C. Is by facilitated diffusion D. Is less than 10% than dietary intake E. Is facilitated by phosphate |
ANSWER A
Diffusion across the apical membrane occurs is passive. Intraceullarly it is bound to carrier proteins (so not to interfere with intracellular processes) Movement across the basolateral membrane is via Ca/ATPase driving against a concentration gradient. 1,25(OH)2D induces both the carrier protein and Ca-ATPase |
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GI16 [Mar03] [Jul03] Bacteria in the intestines:
A. Reduced by the continuous movement of contents through GIT B. Small intestine is sterile C. Bacteria in small intestine and large intestine – same in number but different species D. Required for the absorption?/ breakdown of? E. Reduced in small intestine due to gastric acid & fast motility |
ANSWER E
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GI18 [Feb04] [Jul04] Gastrin secretion is decreased by:
A. Vagus B. Amino acids C. Food in the stomach D. H+ ions in the antrum E. Hyperglycaemia |
ANSWER D
Gastrin secretion is stimulated by: Vagus, Amino acids/Peptides in stomach, Distention of stomach, Cathecolamines Gastrin secretion is inhibited by: Acid in stomach, Secretion, GIP, VIP |
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GI17 [Mar03] [Jul03] Functions of the liver include ALL EXCEPT:
A. ? B. ? |
Massive list
1. metabolic : CHO, protein, fatty acids, biotransformation of drugs, xenobiotics and acid anions 2. storage : fat soluable vitamins (ADEK), metals (Fe and Cu), glycogen, blood 3. Excretion : bilirubin, urea 4. Synthetic : bile, plasma proteins, albumin, acute phase reactions 5. Endocine : 25(OH)2D, EPO 6. Filtration 7. Haemopoesis in neonate |
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GI19 [Feb04] [Jul04] Gastric acid secretion
A. Misoprostolol decreases gastric acid secretion and causes constipation B. Acetylcholine and gastrin cause acid secretion by direct and indirect mechanisms C. Omeprazole causes reversible inhibition of the proton pump on the parietal cell membrane D. Pirenzepine is more effective than omeprazole at reducing gastric acid |
ANSWER B
Answer is B A. Misoprostol is a gastroprotectant but causes diarrhoea (not constipation) (p. 973 & 995) B. Both ACh and gastrin directly and indirectly stimulate gastric acid secretion (p. 967-8) C. Proton pump inhibitors (e.g. omeprazole) irreversibly inactivate the H+,K+-ATPase molecule (p. 969) D. PPIs are the most potent suppressors of gastric acid secretion, while M1 antagonists (e.g. pirenzepine) have poor efficacy (p. 969 & 975) |
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GI20 [Jul04] When the liver's glycogen stores are saturated it converts glucose to
A. ? B. Ketone bodies C. Amino acids D. Triglycerides |
ANSWER D
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GI21 [Jul04] Which of the following is not produced in the liver?
A. Conjugated bilirubin B. Immunoglobulins C. Cholesterol D. Cholecalciferol |
ANSWER B and D
Immunoglobulins produced by plasma cells Cholecalciferol produced in skin |
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GI22 [Jul06] Which of the following is absorbed via micelles? (OR: Micelles aid the absorption of:)
A. vitamin D B. Glycerol C. Bile acids D. Other options more readily identifiable as wrong. E. ? |
ANSWER A
Fat soluable vitamins are absorbed through this route. |
