sinh lý tiêu hóa 1
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Questions and Answers

Which process is responsible for the 'alkaline tide' observed in gastric venous blood after a meal?

  • Absorption of HCO3− from the cell into the blood (correct)
  • Secretion of H+ into the stomach lumen
  • Diffusion of Cl− through apical membrane channels
  • Inhibition of H+-K+ ATPase by the drug omeprazole

    • What is the primary function of the H+-K+ ATPase in the stomach?

  • To facilitate the diffusion of Cl− through the apical membrane
  • To absorb HCO3− from the cell into the blood
  • To inhibit the secretion of HCl in the stomach
  • To secrete H+ and K+ into the stomach lumen (correct)

    • How does the drug omeprazole affect HCl secretion in the stomach?

  • Omeprazole increases the diffusion of Cl- through the apical membrane
  • Omeprazole stimulates the H+-K+ ATPase, increasing HCl secretion
  • Omeprazole has no effect on HCl secretion in the stomach
  • Omeprazole inhibits the H+-K+ ATPase, decreasing HCl secretion (correct)

    • What is the fate of the absorbed HCO3− from the stomach?

    <p>It is secreted back into the gastrointestinal tract in pancreatic secretions</p> Signup and view all the answers

    What is the role of Cl− in the secretion of HCl in the stomach?

    <p>Cl− is secreted into the lumen of the stomach through a separate Cl− channel</p> Signup and view all the answers

    Which of the following is the main mechanism by which gastrin stimulates HCl secretion?

    <p>Indirect stimulation of the parietal cells through the vagus nerve</p> Signup and view all the answers

    What is the primary role of pepsinogen secretion in the digestive process?

    <p>To initiate protein digestion</p> Signup and view all the answers

    Which of the following is the main mechanism by which the intestinal phase of gastric secretion is triggered?

    <p>Presence of amino acids and small peptides</p> Signup and view all the answers

    What is the primary function of HCl secretion in the stomach?

    <p>To activate pepsinogen to pepsin</p> Signup and view all the answers

    Which of the following is the most important stimulus for pepsinogen secretion during the cephalic and gastric phases of digestion?

    <p>Vagal stimulation</p> Signup and view all the answers

    What is the primary physiologic stimulus that initiates gastrin secretion?

    <p>Presence of amino acids like phenylalanine and tryptophan</p> Signup and view all the answers

    What is the mechanism by which gastrin stimulates increased HCl secretion by parietal cells?

    <p>Gastrin stimulates the release of histamine from enterochromaffin-like (ECL) cells, which then acts on parietal cells</p> Signup and view all the answers

    What is the primary function of cholecystokinin (CCK) in the gastrointestinal system?

    <p>Inhibit gastric emptying and increase gastric emptying time</p> Signup and view all the answers

    What is the primary cause of steatorrhea (fat malabsorption) in Zollinger-Ellison syndrome?

    <p>Inactivation of pancreatic lipase due to excessive gastric acid secretion</p> Signup and view all the answers

    What is the primary mechanism by which somatostatin inhibits gastrin secretion?

    <p>Somatostatin directly inhibits the G cells from secreting gastrin</p> Signup and view all the answers

    Which gastrointestinal hormone is primarily responsible for stimulating the contraction of the gallbladder and relaxation of the sphincter of Oddi?

    <p>Cholecystokinin (CCK)</p> Signup and view all the answers

    What is the primary function of the vagus nerve in the regulation of gastrointestinal secretions?

    <p>It stimulates enzyme secretion and potentiates the action of CCK.</p> Signup and view all the answers

    What is the primary function of the bile salts in the small intestine?

    <p>To facilitate the absorption of lipids and fat-soluble vitamins.</p> Signup and view all the answers

    Which enzyme is responsible for the activation of trypsinogen into trypsin in the small intestine?

    <p>Enterokinase</p> Signup and view all the answers

    Which of the following is the primary regulator of HCl secretion in the stomach?

    <p>Gastrin</p> Signup and view all the answers

    Which of the following is the primary regulator of pancreatic enzyme secretion during the intestinal phase?

    <p>Cholecystokinin (CCK)</p> Signup and view all the answers

    What is the effect of the highest pancreatic flow rate on the HCO3- concentration in the pancreatic juice?

    <p>The HCO3- concentration is highest</p> Signup and view all the answers

    Which of the following cell types is responsible for the enzymatic secretion of the pancreas?

    <p>Acinar cells</p> Signup and view all the answers

    Which of the following receptors are present on pancreatic acinar cells?

    <p>CCKA receptors and muscarinic receptors for ACh</p> Signup and view all the answers

    Which phase of pancreatic secretion is initiated by the distention of the stomach and mediated by the vagus nerve?

    <p>Gastric phase</p> Signup and view all the answers

    Which membrane transporter is responsible for actively pumping hydrogen ions (H+) into the gastric lumen, leading to the secretion of hydrochloric acid (HCl)?

    <p>H+-K+ ATPase</p> Signup and view all the answers

    Which second messenger system is primarily involved in the stimulation of HCl secretion by acetylcholine (ACh) and gastrin?

    <p>IP3/Ca2+</p> Signup and view all the answers

    What is the primary function of the Cl- channels located on the apical membrane of parietal cells?

    <p>To provide a pathway for chloride ions (Cl-) to accompany H+ into the gastric lumen</p> Signup and view all the answers

    Which receptor is responsible for mediating the effects of histamine on parietal cells, leading to increased HCl secretion?

    <p>H2 receptor coupled to Gs protein</p> Signup and view all the answers

    Which of the following substances is primarily responsible for regulating the growth and development of the exocrine pancreas?

    <p>Cholecystokinin (CCK)</p> Signup and view all the answers

    What is the function of secretin, as described in the text?

    <p>Inhibition of pancreatic secretion of enzymes</p> Signup and view all the answers

    Which hormone is classified as an incretin and has uncertain physiological roles?

    <p>Glucagon-like peptide-1 (GLP-1)</p> Signup and view all the answers

    What is the primary function of ghrelin, based on the information provided?

    <p>Increasing appetite</p> Signup and view all the answers

    What is the role of leptin in the gastrointestinal system?

    <p>Inhibiting appetite</p> Signup and view all the answers

    Which substance initiates the interdigestive myoelectric complexes that occur at 90-minute intervals?

    <p>Motilin</p> Signup and view all the answers

    What is the function of pancreatic polypeptide as mentioned in the text?

    <p>Inhibition of pancreatic secretion of HCO3- and enzymes</p> Signup and view all the answers

    What is the primary function of the enteric nervous system in the gastrointestinal tract?

    <p>To control the contractile, secretory, and endocrine functions of the gastrointestinal tract</p> Signup and view all the answers

    What is the primary function of the vagus nerve in the regulation of gastrointestinal secretions?

    <p>To coordinate the vagovagal reflexes that regulate gastrointestinal secretions</p> Signup and view all the answers

    What is the primary physiologic stimulus that initiates gastrin secretion from G cells in the stomach?

    <p>Presence of amino acids in the stomach</p> Signup and view all the answers

    What is the main mechanism by which gastrin stimulates $ ext{H}^+$ secretion by parietal cells in the stomach?

    <p>Increase in intracellular cAMP levels</p> Signup and view all the answers

    What is the primary function of the bile salts in the small intestine?

    <p>To emulsify and solubilize dietary fats</p> Signup and view all the answers

    What initiates the interdigestive myoelectric complexes that occur at 90-minute intervals in the gastrointestinal system?

    <p>Motilin</p> Signup and view all the answers

    Which hormone inhibits secretion of other gastrointestinal hormones and inhibits gastric H+ secretion?

    <p>GLP-1</p> Signup and view all the answers

    In the gastrointestinal system, which hormone stimulates anorexigenic neurons and inhibits orexigenic neurons to decrease appetite and increase energy expenditure?

    <p>Leptin</p> Signup and view all the answers

    Which substance inhibits gastric H+ secretion and gastric emptying in the gastrointestinal system?

    <p>Secretin</p> Signup and view all the answers

    What hormone promotes insulin secretion and inhibits gastric H+ secretion in the gastrointestinal system?

    <p>Incretin</p> Signup and view all the answers

    What effect do inhibitory pathways have on the circular muscle in front of the bolus in the small intestine?

    <p>Narrow</p> Signup and view all the answers

    Which neurotransmitter is released in the circular muscle behind the bolus in the small intestine?

    <p>Neuropeptide Y</p> Signup and view all the answers

    What is the primary effect of distention of the stomach by food on the large intestine motility?

    <p>Increases frequency of mass movements</p> Signup and view all the answers

    Which regulatory substance is responsible for stimulating the contraction of the gallbladder and relaxation of the sphincter of Oddi?

    <p>CCK</p> Signup and view all the answers

    How is carbon dioxide (CO2) processed in intracellular fluid?

    <p>Dissociates into H+ and HCO3− catalyzed by carbonic anhydrase</p> Signup and view all the answers

    What is the primary purpose of the retrograde movement (retropulsion) of chyme in the stomach?

    <p>To ensure the food is small enough before moving to the small intestine</p> Signup and view all the answers

    Which of the following is the primary mechanism by which the presence of fat in the duodenum slows gastric emptying?

    <p>Stimulation of CCK secretion, which then inhibits gastric contractions</p> Signup and view all the answers

    What is the primary mechanism by which the presence of H+ ions in the duodenum slows gastric emptying?

    <p>The H+ ions bind to H+ receptors in the duodenal mucosa, which then send a signal to decrease gastric contractions</p> Signup and view all the answers

    What is the primary mechanism by which the enteric nervous system regulates segmentation contractions in the small intestine?

    <p>The food bolus is sensed by enterochromaffin-like (ECL) cells, which then release serotonin (5-HT) to activate the peristaltic reflex</p> Signup and view all the answers

    Which of the following gastrointestinal regulatory substances is primarily responsible for stimulating the contraction of the gallbladder and relaxation of the sphincter of Oddi?

    <p>Cholecystokinin (CCK)</p> Signup and view all the answers

    What is the main mechanism by which ACh stimulates H+ secretion in gastric parietal cells?

    <p>Stimulation of Ca2+/IP3 second messenger system</p> Signup and view all the answers

    What is the primary role of gastrin in stimulating HCl secretion in the stomach?

    <p>Activation of IP3/Ca2+ second messenger system</p> Signup and view all the answers

    Which substance activates protein kinase A in gastric parietal cells to cause H+ secretion?

    <p>Histamine</p> Signup and view all the answers

    What is the final physiologic action produced by the activation of protein kinases in parietal cells?

    <p>H+ secretion by the parietal cells</p> Signup and view all the answers

    Which G protein-coupled receptor is responsible for activating cAMP and subsequently protein kinase A in parietal cells?

    <p>H2 receptor</p> Signup and view all the answers

    What is the primary function of the bile salts in the small intestine?

    <p>To emulsify and solubilize dietary fats, aiding their digestion and absorption</p> Signup and view all the answers

    What is the primary mechanism by which cholecystokinin (CCK) regulates gastrointestinal function?

    <p>Stimulates the contraction of the gallbladder and relaxation of the sphincter of Oddi</p> Signup and view all the answers

    Which enzyme is responsible for the activation of trypsinogen into its active form, trypsin, in the small intestine?

    <p>Enterokinase</p> Signup and view all the answers

    What is the primary function of the enterohepatic circulation of bile salts?

    <p>To conserve and recycle bile salts, which are otherwise lost in the feces</p> Signup and view all the answers

    Which gastrointestinal hormone is primarily responsible for stimulating the secretion of pancreatic enzymes during the intestinal phase of digestion?

    <p>Cholecystokinin (CCK)</p> Signup and view all the answers

    What is the primary physiological stimulus for gastrin secretion?

    <p>Presence of phenylalanine and tryptophan</p> Signup and view all the answers

    Which hormone is responsible for inhibiting gastric emptying and increasing gastric emptying time?

    <p>Cholecystokinin</p> Signup and view all the answers

    What is the main consequence of excessive gastrin secretion in Zollinger-Ellison syndrome?

    <p>Acidification of the intestinal lumen and fat malabsorption</p> Signup and view all the answers

    Which gastrointestinal hormone promotes fat digestion and absorption?

    <p>Cholecystokinin</p> Signup and view all the answers

    What is the function of Zollinger-Ellison syndrome?

    <p>Cause hypertrophy of the gastric mucosa and duodenal ulcers</p> Signup and view all the answers

    What is the primary effect of low pH and somatostatin on gastrin secretion?

    <p>Inhibit gastrin release</p> Signup and view all the answers

    Which gastrointestinal hormone is responsible for the relaxation of the Sphincter of Oddi and ejection of bile from the gallbladder into the lumen?

    <p>Cholecystokinin</p> Signup and view all the answers

    How does gastrin affect the growth of the gastric mucosa?

    <p>Stimulates growth by directly acting on mucosal cells</p> Signup and view all the answers

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