HANDOUT 1 GIT
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Questions and Answers

Which physiological process is responsible for breaking down complex food molecules into simpler substances?

  • Secretion
  • Absorption
  • Motility
  • Digestion (correct)

    • Which control system of GI functions involves the release of chemical messengers such as gastrin and secretin?

  • Muscular control
  • Neural control
  • Hormonal control (correct)
  • Blood flow control

    • What is the main function of neural control in the GI tract?

  • Coordinating muscular contractions for propulsion of food (correct)
  • Regulating blood flow to the GI tract
  • Regulating the release of digestive enzymes
  • Balancing electrolyte levels in the intestines

    • In the context of GI physiology, what is the primary role of smooth muscle cells?

    <p>Generating electrical activity for motility</p> Signup and view all the answers

    Which anatomical structure of the GI tract is primarily responsible for the absorption of nutrients?

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

    What is the main function of blood flow control in the context of GI physiology?

    <p>Delivering oxygen and nutrients to the GI tract</p> Signup and view all the answers

    Which hormone is released from the upper small intestinal specialized cells and is stimulated by fat and carbohydrates in chyme?

    <p>GIP: Gastric Inhibitory Peptide</p> Signup and view all the answers

    What stimulates the release of Secretin?

    <p>Acid in duodenum</p> Signup and view all the answers

    Which type of movement ensures the movement of chyme analward at an appropriate rate?

    <p>Peristaltic Movement</p> Signup and view all the answers

    What is the function of migrating motor complex (MMC)?

    <p>Sweep the intestinal content in the time between meals</p> Signup and view all the answers

    What controls the rhythmic contractions of the longitudinal layer in the intestine?

    <p>Electrical activities of smooth muscle cells</p> Signup and view all the answers

    Which hormone enhances intestinal motility?

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

    How are peristaltic contractions initiated in the GI tract?

    <p>By local reflexes caused by distention of the gut</p> Signup and view all the answers

    What initiates contractile ring 2-3 cm above the distended part and relaxation down to the distension of segment, which moves forward along the GI tract?

    <p><em>Mucosal stimulation</em></p> Signup and view all the answers

    What is the role of the third thin layer of smooth muscle cells known as Muscularis mucosa?

    <p>It is involved in the secretion from tubular glands and movements of mucosal folds</p> Signup and view all the answers

    What causes the appearance of slow waves in smooth muscle cells?

    <p>Metabolic dependent initiation</p> Signup and view all the answers

    Which cells are believed to be the pacemaker cells of the gastrointestinal tract?

    <p>Interstitial Cells of Cajal (ICCs)</p> Signup and view all the answers

    What is the role of interstitial cells of Cajal (ICCs) communication with smooth muscle cells?

    <p>It regulates the rhythm of slow waves in smooth muscle cells</p> Signup and view all the answers

    How do smooth muscle cells respond to a wide range of stimuli caused by neurotransmitters or hormones?

    <p>By activation of receptors on smooth muscle cells</p> Signup and view all the answers

    What are the characteristics of Interstitial Cells of Cajal (ICCs)?

    <p>They have large number of processes and communicate through gap junctions with other ICCs and smooth muscle cells</p> Signup and view all the answers

    What is the source of Ca++ for contraction in smooth muscle cells?

    <p>Both extracellular fluid and sarcoplasmic reticulum</p> Signup and view all the answers

    What is the involuntary stage of deglutition subdivided into?

    <p>Pharyngeal and esophageal stages</p> Signup and view all the answers

    What is the function of the upper esophageal sphincter during deglutition?

    <p>Relaxed to allow the bolus to move into the esophagus</p> Signup and view all the answers

    Which nerve controls the lower third of the esophagus during deglutition?

    <p>Vagus nerve</p> Signup and view all the answers

    What is the role of inhibitory neurons from the lower part of the esophagus?

    <p>Inhibit the tonic contraction of the lower esophageal sphincter</p> Signup and view all the answers

    What pathological condition may result from the failure of the lower esophageal sphincter to relax?

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

    What is the function of receptive relaxation of the stomach?

    <p>Facilitates storage of food in the stomach</p> Signup and view all the answers

    What is responsible for determining the frequency of peristaltic constrictive waves in the stomach?

    <p>Frequency of basic electrical rhythm (BER) of gastric smooth muscle</p> Signup and view all the answers

    What structure prevents passage of food particles into the duodenum until they are well mixed with secretions?

    <p>Pyloric sphincter</p> Signup and view all the answers

    What triggers hunger contractions in the stomach?

    <p>High glucose concentration in blood</p> Signup and view all the answers

    What hormone has a mild stimulatory effect on peristaltic activities of the stomach?

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

    What initiates myenteric reflexes that cause an increase in pyloric pump activity?

    <p>Distension of esophagus by retained food</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 activity of smooth muscle cells in the GI tract</p> Signup and view all the answers

    Which division of the parasympathetic nervous system provides innervations to the esophagus, stomach, pancreas, and small intestine?

    <p>Cranial division</p> Signup and view all the answers

    Which hormone is released from the upper small intestinal specialized cells and is stimulated by fat and carbohydrates in chyme?

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

    What stimulates the release of VIP (Vasoactive Intestinal Peptide) in the enteric nervous system?

    <p>Excessive distension of the gut</p> Signup and view all the answers

    What is the function of motilin in the gastrointestinal tract?

    <p>Enhances intestinal motility</p> Signup and view all the answers

    Which anatomical structure of the GI tract is primarily responsible for the absorption of nutrients?

    <p>Villus and microvilli in the small intestine</p> Signup and view all the answers

    What initiates contractile ring 2-3 cm above the distended part and relaxation down to the distension of segment, which moves forward along the GI tract?

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

    What is the main function of blood flow control in the context of GI physiology?

    <p>To meet the increased demand for nutrients and oxygen during digestion</p> Signup and view all the answers

    Which system causes a decrease in blood flow to the gut through vasoconstriction?

    <p>Sympathetic nervous system</p> Signup and view all the answers

    What is the main responsibility of the haustration contractions in the colon?

    <p>Aiding in the absorption of water and electrolytes</p> Signup and view all the answers

    What initiates the intrinsic reflexes preceding the defecation act?

    <p>Distention of the rectum</p> Signup and view all the answers

    What is the role of mass contractions in the colon?

    <p>Moving fecal materials from the beginning of transverse colon to the sigmoid</p> Signup and view all the answers

    How do the propulsive movements (mass contractions) in the colon appear?

    <p>As constrictive rings that usually begin at the transverse colon</p> Signup and view all the answers

    What is the effect of irritations like ulcerative colitis on the mass movements of the colon?

    <p>Initiates an increase in mass movements of the colon</p> Signup and view all the answers

    What causes feces to move into the rectum, initiating defecation reflex?

    <p>Increased abdominal pressure and closure of glottis</p> Signup and view all the answers

    What is the role of intrinsic reflexes in defecation?

    <p>Initiate signals through myenteric plexus to cause more contractions in descendent colon, sigmoid, and rectum</p> Signup and view all the answers

    What represents the appearance of haustration contractions in the colon?

    <p>Rhythmic contraction and relaxation of circular layer of colonic smooth muscle cells at a length of about 2.5cm</p> Signup and view all the answers

    What is the effect of gastrocolic and duodenocolic reflexes on mass contractions?

    <p>Facilitate mass contractions in the colon</p> Signup and view all the answers

    What represents propulsive movements (mass contractions) in the colon?

    <p>Series of contractions that appear 1-3 times/day and last each time about 10-30 minutes</p> Signup and view all the answers

    How do intrinsic reflexes contribute to defecation?

    <p>Signals through myenteric plexus (ENS) to cause more contractions in descendent colon, sigmoid, and rectum</p> Signup and view all the answers

    What is responsible for increasing mass movements of the colon in cases like ulcerative colitis?

    <p>Irritation of the mucosa causing increase in mass movements of the colon</p> Signup and view all the answers

    Is the primary function of the enteric nervous system in the gastrointestinal tract related to the release of chemical messengers such as gastrin and secretin?

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

    Does the hormone Motilin have a role in enhancing intestinal motility?

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

    Are interstitial cells of Cajal (ICCs) believed to be the pacemaker cells of the gastrointestinal tract?

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

    Is neural control the main system responsible for determining the frequency of peristaltic constrictive waves in the stomach?

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

    Does Vasoactive Intestinal Peptide (VIP) stimulate the release of Secretin in the enteric nervous system?

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

    Is the effect of gastrocolic and duodenocolic reflexes on mass contractions a decrease in blood flow to the gut through vasoconstriction?

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

    The myenteric plexus, also known as Auerbach’s plexus, controls gastrointestinal movements.

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

    The submucosal plexus, also known as Meissner’s plexus, primarily controls gastrointestinal blood flow.

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

    The parasympathetic nervous system provides innervations through vagus nerve to the distal half of the colon, sigmoidal, rectum, and anal region.

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

    Sympathetic stimulation causes vasoconstriction, resulting in decreased blood flow to the gut.

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

    Gastrin and Secretin release vasodilator substances after mucosal stimulation caused by meals.

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

    The increase in absorption, secretion, and motor activities in the gut after a meal is accompanied by a decrease in blood flow.

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

    Parasympathetic stimulation causes an increase in blood flow to the gut.

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

    The initiation of chewing reflex is stimulated by smell and taste to cause chewing of food in the mouth.

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

    The presence of food bolus in the mouth causes activation of the stretch reflex, leading to the initiation of chewing reflex.

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

    Chewing results in grinding action on food to get smaller particles.

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

    Mastication primarily occurs due to muscle stretching caused by the drop of the lower jaw.

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

    Chewing reflex centers in hypothalamus and cerebral cortex are stimulated by muscle stretching caused by drop of the lower jaw.

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

    The activity of muscularis mucosa is responsible for the shortening and elongating mucosal folds.

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

    Haustration contractions of the colon are similar to segmentation contractions of the small intestine.

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

    Mass contractions appear 1-3 times a day and last for 10-30 minutes each time.

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

    Gastrocolic and duodenocolic reflexes facilitate mass contractions in the colon.

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

    Defecation in normal people occurs as a voluntary act by relaxing the external sphincter.

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

    Intrinsic reflexes preceding defecation act cause more contractions in ascending colon and rectum.

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

    Extrinsic reflexes result in signals to the internal sphincter to cause relaxation during defecation.

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

    All defecation reflexes are involuntary.

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

    Muscularis mucosa is involved in causing haustral appearance in the colon.

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

    The contractions caused by muscularis mucosa are affected by the activity of the enteric nervous system.

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

    Proximal colonic content is mainly moved by haustration contractions.

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

    Mass movements may be initiated by irritation of the colon, such as in ulcerative colitis.

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

    Smooth muscle cells in the gastrointestinal tract are characterized by the presence of fast waves and spike potentials.

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

    The release of Ca++ from sarcoplasmic reticulum in smooth muscle cells occurs by formation of IP3 resulting from signal transduction mechanisms.

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

    Smooth muscle cells respond to a limited range of stimuli caused by neurotransmitters or hormones.

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

    The 4 cells of Cajal play an insignificant role in the synchronization of smooth muscle cells activity.

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

    Slow waves in smooth muscle cells are believed to be dependent on mechanical factors rather than metabolic factors.

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

    The tonic contraction by smooth muscle cells is independent of the binding of ligands to their receptor.

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

    The electrical activity of smooth muscle cells is solely controlled by the neurochemical system.

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

    Interstitial Cells of Cajal (ICCs) are incapable of eliciting electrical activity as action potentials.

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

    The entry of Ca++ from the interstitial fluid into smooth muscle cells occurs independently of any activation.

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

    Smooth muscle cells do not form syncytium, and each cell functions independently.

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

    The third thin layer of smooth muscle cells known as Muscularis mucosa is not involved in movements of mucosal folds or secretion from tubular glands.

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

    The characteristic slow waves in smooth muscle cells represent undulating changes in membrane potential known as basic electrical rhythm (BER).

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

    Decreased pH in the duodenum causes an increase in gastric emptying.

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

    CCK (cholecystokinin) is released from the jejunum and its release is stimulated by fat in chyme.

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

    GIP (Gastric Inhibitory Peptide) is released from upper small intestinal specialized cells and is stimulated by protein in chyme.

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

    Peristaltic contractions move food along the GI tract and are caused by rhythmic shortening of the circular muscle layer.

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

    The enteric nervous system has no role in controlling gastrointestinal functions, including movements and rate of chyme movements.

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

    Hormones like secretin and glucagon enhance intestinal motility.

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

    Circular smooth muscle cells provide mixing of food with GI secretions in the GI tract through segmentation contractions.

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

    The maximum frequency of segmentation contractions is about 12/minute in the terminal ileum.

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

    Migrating Motor Complex (MMC) primarily occurs during digestive periods.

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

    The function of Migrating Motor Complex (MMC) is to propel chyme in the oralward direction.

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

    Deglutition has three stages: voluntary, pharyngeal, and esophageal.

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

    An effective peristaltic activity to cause a propulsive movement of chyme requires an intact and active enteric nervous system.

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

    The primary peristaltic contractions in the esophagus continue the contractions initiated in the pharynx.

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

    Parasympathetic nervous system modulates the peristaltic activities by changing the activity of neural network or by changing the activity of smooth muscle cells.

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

    The lower esophageal sphincter relaxes to allow the bolus to move into the esophagus.

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

    Achalasia occurs when the ability of myenteric plexus to cause relaxation of the sphincter has failed.

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

    The pyloric sphincter constricts to impede emptying of chyme into the stomach.

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

    The pyloric pump refers to the process that results in gastric emptying.

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

    Pylorus is a large opening between the stomach and duodenum.

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

    Hunger contractions in the stomach are rhythmical peristaltic contractions that appear when the stomach is full.

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

    Gastrin has a mild stimulatory effect on the peristaltic activities of the stomach.

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

    Filling of the stomach inhibits the tone of pyloric sphincter.

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

    Interstitial cells of Cajal (ICCs) communicate with smooth muscle cells to initiate hunger contractions in the stomach.

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

    Irritations like ulcerative colitis enhance mass contractions of the colon.

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

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