Salivary and Gastrointestinal Physiology Quiz
47 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of α-amylase in saliva?

  • Digestion of carbohydrates (correct)
  • Digestion of proteins
  • Emulsification of fats
  • Neutralization of acids

    • Which of the following is NOT a characteristic of saliva?

  • High concentrations of K<sup>+</sup>
  • Isotonicity (correct)
  • Hypotonicity
  • Presence of lingual lipase

    • Which factor primarily stimulates gastric secretion?

  • Gastrin (correct)
  • Secretin
  • Bile salts
  • Vagus nerve discharge

    • What is the effect of atropine on saliva production?

    <p>Decreases saliva secretion</p> Signup and view all the answers

    Which component is not typically found in pancreatic secretions?

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

    What regulates the flow rate of saliva secretion?

    <p>Nervous system stimulation</p> Signup and view all the answers

    What characterizes high flow rates of saliva secretion?

    <p>Composition closest to plasma</p> Signup and view all the answers

    What is the primary second messenger involved in the action of anticholinergic drugs on saliva production?

    <p>Inositol 1,4,5-triphosphate (IP3)</p> Signup and view all the answers

    Which cells in the gastric mucosa are responsible for secreting HCl and intrinsic factor?

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

    What role do myoepithelial cells play in saliva production?

    <p>They contract to eject saliva into the mouth.</p> Signup and view all the answers

    What effect does sympathetic stimulation have on saliva production compared to parasympathetic stimulation?

    <p>Increases the production, but less than parasympathetic stimulation</p> Signup and view all the answers

    What does the drug omeprazole inhibit in gastric cells?

    <p>H+, K+-ATPase in parietal cells</p> Signup and view all the answers

    What happens to the ionic composition of saliva as it passes through the ducts?

    <p>Na+ and Cl- are reabsorbed while K+ and HCO3- are secreted.</p> Signup and view all the answers

    How does saliva composition differ at high flow rates compared to low flow rates?

    <p>Saliva has lower K+ concentration at high flow rates.</p> Signup and view all the answers

    What occurs in the bloodstream when HCO3- is produced by parietal cells during gastric secretion?

    <p>The pH of the blood increases, causing alkaline tide</p> Signup and view all the answers

    What substances do chief cells secrete in the gastric body?

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

    What is the primary method of regulating saliva production?

    <p>By both the parasympathetic and sympathetic nervous systems.</p> Signup and view all the answers

    What effect does dehydration have on saliva production?

    <p>Decreases saliva production</p> Signup and view all the answers

    Which cranial nerves are primarily responsible for parasympathetic stimulation of saliva production?

    <p>Cranial nerves VII and IX</p> Signup and view all the answers

    What is the expected effect of aldosterone on ductal cells?

    <p>It increases Na+ reabsorption.</p> Signup and view all the answers

    What is the consequence of vomiting on the secretion of gastric H+ and pancreatic HCO3-?

    <p>Both gastric H+ and pancreatic HCO3- secretion are prevented</p> Signup and view all the answers

    Why does saliva become hypotonic as it passes through the ducts?

    <p>Because the ducts reabsorb more solute than water.</p> Signup and view all the answers

    What effect does sympathetic stimulation have on saliva production compared to parasympathetic stimulation?

    <p>Sympathetic stimulation is less important than parasympathetic.</p> Signup and view all the answers

    What mechanism explains the inhibition of gastric H+ secretion when low pH is detected in the stomach?

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

    How does somatostatin contribute to the inhibition of gastric H+ secretion?

    <p>By inhibiting the release of histamine and gastrin</p> Signup and view all the answers

    What role do prostaglandins play in gastric secretion?

    <p>They activate G<sub>i</sub> proteins to inhibit H<sup>+</sup> secretion</p> Signup and view all the answers

    Which of the following factors are considered protective against peptic ulcer disease?

    <p>Prostaglandins, mucus, and HCO<sub>3</sub><sup>-</sup></p> Signup and view all the answers

    What is a direct consequence of gastric H+ secretion leaking back through damaged gastric mucosa?

    <p>Development of gastric ulcers</p> Signup and view all the answers

    Which factor is NOT considered damaging in peptic ulcer disease?

    <p>Mucosal blood flow</p> Signup and view all the answers

    How do negative feedback mechanisms regulate gastric H+ secretion?

    <p>They inhibit further secretion when pH is below 3.0</p> Signup and view all the answers

    What is a potential consequence of excessive secretion of H+ and pepsin?

    <p>Loss of the mucosal barrier</p> Signup and view all the answers

    What is the primary secretion product of parietal cells in the stomach?

    <p>HCl and Intrinsic factor</p> Signup and view all the answers

    Chief cells in the stomach secrete which of the following substances?

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

    Which factors stimulate gastric secretion from G cells?

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

    What role does bicarbonate (HCO3-) play in pancreatic secretion?

    <p>It neutralizes acidic chyme in the duodenum</p> Signup and view all the answers

    At low flow rates, pancreatic secretion primarily contains which ions?

    <p>Na+ and Cl-</p> Signup and view all the answers

    What modification do ductal cells perform on the initial pancreatic secretion?

    <p>They secrete HCO3- and absorb Cl-</p> Signup and view all the answers

    Which of the following statements about pancreatic secretion is FALSE?

    <p>Ductal cells are primarily responsible for secreting enzymes.</p> Signup and view all the answers

    What inhibits the secretion of gastrin from G cells?

    <p>Somatostatin and H+ concentration</p> Signup and view all the answers

    Where are bile salts positioned within a micelle?

    <p>On the outside, with hydrophilic portions in the aqueous solution and hydrophobic portions in the micelle interior</p> Signup and view all the answers

    Which agents are known to increase the formation of bile?

    <p>Choleretic agents</p> Signup and view all the answers

    What happens to primary bile acids in the intestine?

    <p>They are converted to secondary bile acids by bacteria</p> Signup and view all the answers

    What is one of the roles of cholecystokinin (CCK) in digestion?

    <p>To signal the gallbladder to contract and release bile</p> Signup and view all the answers

    What occurs during gallbladder contraction?

    <p>Bile is pushed into the duodenum</p> Signup and view all the answers

    What happens to bile acids after ileal resection?

    <p>They are excreted in feces, leading to fat absorption impairment</p> Signup and view all the answers

    What is the role of the Na+–bile acid cotransporter in the terminal ileum?

    <p>To facilitate the recirculation of bile acids to the liver</p> Signup and view all the answers

    How is bile concentrated while stored in the gallbladder?

    <p>Via isosmotic absorption of solutes and water</p> Signup and view all the answers

    Study Notes

    Gastrointestinal (GI) Secretions

    • Saliva is characterized by a high concentration of HCO3⁻, K⁺, and a low concentration of Na⁺ and Cl⁻.

    • Saliva is stimulated by the parasympathetic and sympathetic nervous systems.

    • Saliva production is inhibited by sleep and dehydration.

    • Gastric secretion involves the production of hydrochloric acid (HCl) and is regulated by the parasympathetic nervous system, gastrin, and histamine.

    • Gastric secretion is inhibited by low stomach pH and the presence of chyme in the duodenum.

    • Pancreatic secretion involves the output of enzymes, and is regulated by secretin and cholecystokinin (CCK). CCK also causes the gallbladder to contract.

    • Pancreatic secretion is stimulated by the parasympathetic nervous system and CCK.

    • Bile is produced by the liver and stored in the gallbladder. It involves bile salts, phospholipids, cholesterol, and bilirubin.

    • Bile is stimulated by CCK, which causes the gallbladder to contract.

    Salivary Secretion

    • Saliva functions to digest starches with a-amylase (ptyalin), and also digests triglycerides.
    • Saliva involves lubrication of food and protection of the mouth and esophagus.
    • The production of saliva is affected by flow rate: a higher rate results in lower osmolarity.

    Gastric Secretion

    • Parietal cells produce HCl and intrinsic factor.

    • Chief cells produce pepsinogen.

    • G cells produce gastrin.

    • Gastric H⁺ secretion involves a direct and indirect pathway stimulated by vagal stimulation.

    • Negative feedback mechanisms involving low pH in the stomach, somatostatin, and prostaglandins regulate H⁺ secretion in parietal cells.

    Pancreatic Secretion

    • Pancreatic secretion contains high HCO3⁻, and similar levels of Na⁺ and K⁺ as in plasma, but low levels of Cl⁻.
    • The composition of pancreatic secretion varies depending on flow rate: low rate = isotonic with high levels of Na⁺ and Cl⁻, high rate = isotonic with high levels of Na⁺ and HCO3⁻.
    • Enzymes like lipase, amylase, and proteases are found in pancreatic secretions.
    • Pancreatic secretion production is stimulated by secretin, CCK and ACh.

    Bile Secretion and Gallbladder Function

    • Bile contains bile salts, phospholipids, cholesterol, and bile pigments.
    • Bile salts emulsify and solubilize lipids in micelles to aid in lipid digestion and absorption.
    • Bile is formed and released by hepatocytes (in the liver), and it's stored and concentrated in the gallbladder until needed by the small intestine.
    • Bile secretion is stimulated or inhibited by CCK and ACh, respectively.
    • Bile and bile acids are recycled in the small intestine and transported back to the liver.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Gastrointestinal Secretion (Table 6.2) PDF

    Description

    Test your knowledge on the functions and characteristics of saliva and the gastrointestinal system. This quiz covers various aspects such as secretion mechanisms, regulation, and the effects of different drugs on saliva and gastric functions. Perfect for students in physiology or related courses.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser