Regulation of Gut Motility Functions Quiz
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Questions and Answers

What initiates the basic electrical rhythm (BER) in the gastrointestinal tract?

  • Smooth muscle cells
  • Neurons from the central nervous system
  • Interstitial cells of Cajal (correct)
  • Myenteric plexus cells

    • Where are the cells of Cajal located in the stomach and small intestine?

  • Submucosal border of the longitudinal muscle layer
  • Inner longitudinal muscle layer near the serosa
  • Outer circular muscle layer near the myenteric plexus (correct)
  • Inner circular muscle layer near the submucosa

    • What is the role of spike potentials superimposed on the depolarizing portions of the BER waves?

  • Inhibit muscle tension
  • Maintain membrane potential
  • Stimulate neurotransmitter release
  • Increase muscle tension (correct)

    • What ion is responsible for the depolarizing portion of spike potentials in the gastrointestinal tract?

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

    In what part of the gastrointestinal tract does the BER rarely cause muscle contraction?

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

    Which region of the gastrointestinal tract exhibits a descending gradient in pacemaker frequency?

    <p>Small intestine</p> Signup and view all the answers

    What happens to gastric secretion, bile flow, and pancreatic secretion during each MMC?

    <p>They increase</p> Signup and view all the answers

    What occurs when a meal is ingested in relation to motilin secretion and MMC?

    <p>Motilin secretion is suppressed</p> Signup and view all the answers

    What is the role of erythromycin in gastrointestinal motility?

    <p>It binds to motilin receptors</p> Signup and view all the answers

    What triggers receptive relaxation in the stomach?

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

    How does the stomach accommodate food upon entry?

    <p>Through receptive relaxation</p> Signup and view all the answers

    What initiates peristaltic waves in the stomach after food entry?

    <p>Gastric BER control</p> Signup and view all the answers

    What is the primary function of the colon in relation to fluid absorption?

    <p>Convert isotonic chyme to semiliquid feces</p> Signup and view all the answers

    What is the role of the ileocecal valve in the digestive process?

    <p>Act as a barrier to prevent reflux into the relatively sterile ileum</p> Signup and view all the answers

    What happens when peristaltic waves reach the ileocecal valve?

    <p>The valve opens briefly to allow some ileal chyme to enter the cecum</p> Signup and view all the answers

    Which reflex is responsible for increasing passage through the ileocecal valve when food leaves the stomach?

    <p>Gastro-ileal reflex</p> Signup and view all the answers

    What is a common feature between segmentation contractions in the colon and small intestine?

    <p>They mix and expose contents to mucosa for absorption</p> Signup and view all the answers

    What is the function of antiperistalsis occasionally seen in the colon?

    <p>Reverse direction of movement in specific cases</p> Signup and view all the answers

    What is the main physiological mechanism through which fats, carbohydrates, and acid in the duodenum inhibit gastric acid and pepsin secretion?

    <p>Neural and hormonal mechanisms</p> Signup and view all the answers

    Which hormone has been identified as possibly being the messenger involved in inhibiting gastric acid and pepsin secretion in the duodenum?

    <p>Peptide YY</p> Signup and view all the answers

    What is the role of CCK in gut motility?

    <p>Inhibitor of gastric emptying</p> Signup and view all the answers

    What initiates the process of vomiting?

    <p>Salivation and sensation of nausea</p> Signup and view all the answers

    Why does the glottis close during vomiting?

    <p>To prevent aspiration of vomitus into the trachea</p> Signup and view all the answers

    Which region of the brain contains the 'vomiting center' responsible for controlling different components of the vomiting act?

    <p>Reticular formation of the medulla</p> Signup and view all the answers

    What initiates the defecation reflex?

    <p>Rectal distension</p> Signup and view all the answers

    How does the frequency of the wave in the colon change along its length?

    <p>Increases from the ileocecal valve to the sigmoid colon</p> Signup and view all the answers

    How long does it take for the first remnants of a meal to reach the terminal part of the colon?

    <p>12 hours</p> Signup and view all the answers

    What percentage of small colored beads fed with a meal are typically recovered in the stool after 72 hours?

    <p>70%</p> Signup and view all the answers

    What does monitoring a pill containing sensors and a miniature radio transmitter allow observation of within the gastrointestinal tract?

    <p>Transit time, pressure fluctuations, and pH changes</p> Signup and view all the answers

    What type of contraction occurs exclusively in the colon?

    <p>Mass action contraction</p> Signup and view all the answers

    What is the function of motilin during the MMC?

    <p>Promotes peristalsis and spike potentials</p> Signup and view all the answers

    How does erythromycin impact gastrointestinal motility?

    <p>Binds to motilin receptors</p> Signup and view all the answers

    What initiates peristalsis in the lower portion of the stomach?

    <p>Intrinsic reflexes</p> Signup and view all the answers

    Which compound may have therapeutic value in patients with decreased gastrointestinal motility?

    <p>Erythromycin derivatives</p> Signup and view all the answers

    What occurs in the stomach during receptive relaxation?

    <p>Accommodation of food without pressure increase</p> Signup and view all the answers

    Which process is suppressed during a meal ingestion?

    <p>Peristalsis and MMC</p> Signup and view all the answers

    What initiates the basic electrical rhythm (BER) in the gastrointestinal tract?

    <p>Interstitial cells of Cajal</p> Signup and view all the answers

    What ions are responsible for the depolarizing and repolarizing portions of spike potentials in the gastrointestinal tract?

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

    Where are the cells of Cajal primarily located in the stomach and small intestine?

    <p>Outer circular muscle layer near myenteric plexus</p> Signup and view all the answers

    What role do neurotransmitters play in affecting the BER in the gastrointestinal tract?

    <p>Enhance BER frequency</p> Signup and view all the answers

    What is the main function of spike potentials superimposed on the BER waves in the gastrointestinal tract?

    <p>Increase muscle tension</p> Signup and view all the answers

    What effect does the location of interstitial cells of Cajal have on pacemaker frequency in the gastrointestinal tract?

    <p>Descending gradient in pacemaker frequency</p> Signup and view all the answers

    What is the primary function of peptide YY in the gastrointestinal system?

    <p>Inhibiting gastric acid and pepsin secretion</p> Signup and view all the answers

    Which of the following statements about vomiting is true?

    <p>Vomiting involves the closure of the glottis to protect the lungs</p> Signup and view all the answers

    What is the role of CCK in relation to gastric emptying?

    <p>Inhibiting gastric emptying</p> Signup and view all the answers

    Which of the following does NOT occur during the process of vomiting?

    <p>Opening of the lower esophageal sphincter</p> Signup and view all the answers

    What triggers the sensation of nausea before vomiting occurs?

    <p>Impulses from the vestibular nuclei</p> Signup and view all the answers

    Which part of the brain contains the 'vomiting center' that controls different components of the vomiting act?

    <p>Medulla reticular formation</p> Signup and view all the answers

    What is the main purpose of slowing motility in the colon?

    <p>To facilitate absorption of water, Na+, and minerals</p> Signup and view all the answers

    What is the function of the ileocecal valve in relation to the colon and ileum?

    <p>Restricts passage of commensal bacteria from the ileum to the colon</p> Signup and view all the answers

    What physiological mechanism facilitates absorption in the colon?

    <p>Segmentation contractions</p> Signup and view all the answers

    What initiates the gastro-ileal reflex leading to an increased flow through the ileocecal valve?

    <p>Exit of food from the stomach</p> Signup and view all the answers

    What type of waves propel the contents of the colon towards the rectum?

    <p>Strong peristaltic waves</p> Signup and view all the answers

    Which segmental contractions promote mixing and absorption in the colon?

    <p>Segmentation contractions</p> Signup and view all the answers

    What type of contraction occurs exclusively in the colon?

    <p>Mass action contraction</p> Signup and view all the answers

    What initiates the defecation reflex?

    <p>Rectal distension</p> Signup and view all the answers

    Which part of the colon has the highest frequency of contraction waves per minute?

    <p>Sigmoid colon</p> Signup and view all the answers

    What is the average transit time for the first remnants of a meal to reach the terminal part of the colon?

    <p>12 hours</p> Signup and view all the answers

    How long does it typically take for total recovery of small colored beads fed with a meal in the stool?

    <p>1 week</p> Signup and view all the answers

    What allows observation of transit time, pressure fluctuations, and pH changes in the gastrointestinal tract?

    <p>Using sensors within a pill</p> Signup and view all the answers

    What is the main purpose of segmentation in the intestines?

    <p>To mix chyme with digestive juices</p> Signup and view all the answers

    Which neurotransmitter is responsible for producing relaxation ahead of the stimulus in the intestines?

    <p>Nitric oxide (NO)</p> Signup and view all the answers

    What describes the motility pattern related to peristalsis that retards movement of intestinal contents?

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

    Which neurotransmitter activates sensory neurons that activate the myenteric plexus?

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

    What is the primary function of cholinergic neurons passing in a retrograde direction in the myenteric plexus?

    <p>Produce smooth muscle contraction behind the bolus</p> Signup and view all the answers

    Which type of contraction occurs routinely in the setting of segmentation in the intestines?

    <p>Retrograde movement of chyme</p> Signup and view all the answers

    What is the primary function of motilin during the MMC?

    <p>Clearing stomach and small intestine of luminal contents</p> Signup and view all the answers

    What triggers receptive relaxation in the stomach?

    <p>Movement of the pharynx and esophagus</p> Signup and view all the answers

    Which compound may have therapeutic value in patients with decreased gastrointestinal motility?

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

    What effect does a meal ingestion have on secretion of motilin and the MMC?

    <p>Suppresses motilin secretion and abolishes MMC</p> Signup and view all the answers

    What initiates peristaltic waves in the stomach after food entry?

    <p>BER controlled waves</p> Signup and view all the answers

    What is the role of the ileocecal valve in the digestive process?

    <p>Controlling passage from small intestine to colon</p> Signup and view all the answers

    What is the primary function of peptide YY in the gastrointestinal system?

    <p>Inhibiting gastric acid and pepsin secretion</p> Signup and view all the answers

    Which part of the brain contains the 'vomiting center' responsible for controlling different components of the vomiting act?

    <p>Reticular formation of the medulla</p> Signup and view all the answers

    What initiates the process of vomiting?

    <p>Irritation of upper gastrointestinal tract mucosa</p> Signup and view all the answers

    Why does the glottis close during vomiting?

    <p>To prevent aspiration into the trachea</p> Signup and view all the answers

    What is an example of central regulation of gut motility functions?

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

    Which messenger is probably involved in inhibiting gastric acid and pepsin secretion and gastric motility in the duodenum?

    <p>Peptide YY</p> Signup and view all the answers

    Which area of the brain is responsible for initiating vomiting in response to certain chemical agents?

    <p>Area Postrema</p> Signup and view all the answers

    What type of receptors in the small intestine trigger impulses that lead to vomiting?

    <p>5-HT3 receptors</p> Signup and view all the answers

    What is the role of ondansetron and haloperidol in treating vomiting?

    <p>Act as effective antiemetic agents</p> Signup and view all the answers

    Which of the following is a condition where lesions of the area postrema decrease vomiting?

    <p>Radiation sickness</p> Signup and view all the answers

    What is the primary function of serotonin (5-HT) released from enterochromaffin cells in the small intestine?

    <p>Trigger impulses for vomiting</p> Signup and view all the answers

    In which part of the brain are dopamine D2 receptors and 5-HT3 receptors primarily located?

    <p>Area Postrema</p> Signup and view all the answers

    What is the function of peristalsis in the small intestine?

    <p>To propel intestinal contents towards the large intestines</p> Signup and view all the answers

    Which muscle contractions are initiated by focal increases in Ca2+ influx in the small intestine?

    <p>Segmentation contractions</p> Signup and view all the answers

    What is the main function of the colon in relation to meal residues?

    <p>To serve as a reservoir for undigested residues</p> Signup and view all the answers

    What is the average frequency of BER cycles/min in the distal ileum of the small intestine?

    <p>8 cycles/min</p> Signup and view all the answers

    How do segmentation contractions in the small intestine affect chyme?

    <p>Increase exposure of chyme to the mucosal surface</p> Signup and view all the answers

    What is the impact of tonic contractions on transit time in the small intestine?

    <p>Tonic contractions slow down transit time</p> Signup and view all the answers

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