Anatomy & Physiology of Gastrointestinal Tract
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Questions and Answers

Which structure is predominantly composed of proliferating B lymphocytes and provides protection against pathogenic bacteria?

  • Peyer’s patches (correct)
  • Celiac plexus
  • Hepatic portal vein
  • Superior mesenteric artery
  • What type of innervation is associated with the vagus nerve in the gastrointestinal system?

  • Sympathetic innervation
  • Motor innervation
  • Parasympathetic innervation (correct)
  • Sensory innervation
  • Which blood vessel is responsible for draining blood from the small intestine into the liver?

  • Hepatic portal vein (correct)
  • Inferior mesenteric artery
  • Thoracic splanchnic nerve
  • Superior mesenteric artery
  • What type of enzyme is found on the brush border of microvilli and is essential for completing food digestion?

    <p>Brush border enzymes</p> Signup and view all the answers

    Which of the following is NOT a function of the sympathetic innervation in the gastrointestinal system?

    <p>Increasing blood flow to the digestive organs</p> Signup and view all the answers

    Where in the gastrointestinal tract are Peyer’s patches predominantly located?

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

    What is the primary function of the peritoneum?

    <p>To bind organs together and hold them in place</p> Signup and view all the answers

    Which layer of the gastrointestinal tract is responsible for secreting slippery fluid to prevent friction?

    <p>Serosa/adventitia</p> Signup and view all the answers

    What does the greater omentum arise from?

    <p>Greater curvature of the stomach</p> Signup and view all the answers

    Which peritoneum layer lines the abdominal and pelvic cavities?

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

    Which organs are referred to as retroperitoneal organs?

    <p>Organs that are situated behind the peritoneum</p> Signup and view all the answers

    What are intraperitoneal organs mainly characterized by?

    <p>Their retention of mesentery during development</p> Signup and view all the answers

    Which layer is not typically found in the esophagus's structure?

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

    What type of tissue primarily forms the serosa layer of the gastrointestinal tract?

    <p>Simple squamous epithelium</p> Signup and view all the answers

    What initiates the motility in the gastrointestinal tract?

    <p>Calcium influx through L-type calcium channels</p> Signup and view all the answers

    How often do slow waves occur in the duodenum?

    <p>12 cycles/minute</p> Signup and view all the answers

    What happens to the frequency of slow waves from the duodenum to the colon?

    <p>It decreases</p> Signup and view all the answers

    Which of the following substances acts as an excitatory stimulant in gastrointestinal motility?

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

    Peristaltic contractions in the stomach primarily originate from which region?

    <p>Upper fundus</p> Signup and view all the answers

    Which type of stimulants inhibit gastrointestinal motility?

    <p>Inhibitory stimulants such as norepinephrine</p> Signup and view all the answers

    What is the primary function of the cardiac sphincter?

    <p>To prevent acidic contents from moving up to the esophagus</p> Signup and view all the answers

    Which cells in the stomach produce hydrochloric acid (HCl)?

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

    What initiates the chemical breakdown of carbohydrates in the oral cavity?

    <p>Salivary amylase</p> Signup and view all the answers

    Which structure allows for the transfer of food from the esophagus to the stomach?

    <p>Cardiac orifice</p> Signup and view all the answers

    What type of epithelium changes at the Z-line of the gastroesophageal junction?

    <p>Stratified squamous to simple columnar</p> Signup and view all the answers

    Which layer in the muscularis externa of the stomach is unique and allows for vigorous contractions?

    <p>Inner oblique layer</p> Signup and view all the answers

    What physiological process primarily occurs within the small intestine?

    <p>Main site for nutrient absorption</p> Signup and view all the answers

    What type of secretion is primarily produced by the pyloric glands?

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

    What is the primary role of saliva in the oral cavity?

    <p>Chemical digestion and lubrication</p> Signup and view all the answers

    Which structure regulates gastric emptying into the duodenum?

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

    What is the primary function of mechanical digestion?

    <p>Increasing the surface area of food for enzymatic digestion</p> Signup and view all the answers

    What initiates the muscle contractions in a syncytium?

    <p>Electrical signals propagated through gap junctions</p> Signup and view all the answers

    What is the normal resting membrane potential of GI smooth muscles?

    <p>-50mV to -60mV</p> Signup and view all the answers

    Which type of waves are responsible for generating the slow wave potential in the GI tract?

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

    What role do exocrine glands play in digestion?

    <p>They secrete digestive juices into the digestive tract lumen</p> Signup and view all the answers

    What is the primary purpose of absorption in the GI tract?

    <p>Absorbing digested nutrients into blood or lymph</p> Signup and view all the answers

    Study Notes

    Anatomy Overview

    • The alimentary or gastrointestinal (GI) tract is a continuous muscular tube extending from the mouth to the anus.
    • Major digestive organs are located in the abdominal and pelvic cavity and are supported by a structure called mesentery.

    Peritoneum

    • A thin connective tissue featuring mesothelium, supports abdominal organs, and contains blood vessels, lymphatics, and nerves.
    • Two layers: parietal peritoneum (covers the cavity) and visceral peritoneum (covers organs).
    • The peritoneal cavity is the space between the parietal and visceral layers.
    • Intraperitoneal organs remain in the peritoneal cavity during embryonic development.

    GI Tract Layers

    • Four basic tissue layers from esophagus to anus:
      • Serosa/Adventitia: Outermost layer, prevents friction.
      • Muscularis Propria: Contains smooth muscle layers for peristalsis.
      • Submucosa: Layer with mucus-secreting glands and blood vessels.
      • Mucosa: Innermost layer responsible for secretion and absorption.

    Oral Cavity

    • Functions in ingestion, mechanical and chemical digestion, and propulsion of food.
    • Saliva contains enzymes like salivary amylase and antibacterial properties.
    • There is mechanical digestion through mastication, and chemical digestion begins in the oral cavity.

    Esophagus

    • A muscular tube connecting the laryngopharynx to the stomach.
    • Contains upper and lower esophageal sphincters that regulate the movement of food and prevent acid reflux.
    • Muscular contractions (peristalsis) propel food into the stomach.

    Stomach

    • Located in the upper left abdominal quadrant, responsible for churning, digestion, and storage of food.
    • Contains regions: cardia (entry point), fundus (storage), body (largest area), and pylorus (connected to the duodenum).
    • Produces gastric juices:
      • Mucus cells protect the lining.
      • Parietal cells produce HCl.
      • Chief cells secrete pepsinogen, initiating protein digestion.

    Small Intestine

    • Main site for digestion and nutrient absorption, featuring circular folds, villi, and microvilli to maximize surface area.
    • Blood supply from the superior mesenteric artery; absorbs nutrients into the hepatic portal circulation.
    • Peyer’s patches in ileum act as protective lymphatic tissue.

    GI Motility

    • Peristalsis moves food through the GI tract, initiated by swallowing and regulated by electrical signals.
    • Normal resting membrane potential of GI smooth muscle is between -50mV to -60mV.
    • Two types of electrical waves:
      • Slow Waves: Generated by pacemaker cells, setting the rhythm of contractions.
      • Action Potentials: Triggered when slow-wave threshold is reached, activating muscle contractions.

    Key Concepts

    • Digestion involves complex food breakdown, secretion of digestive juices, absorption of nutrients, and elimination of waste.
    • Each organ in the GI tract has specialized functions and cellular structures catering to its role in the digestive process.

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    Related Documents

    Anatomy and Physiology PDF

    Description

    This quiz focuses on key concepts and structures within the gastrointestinal anatomy and physiology. It covers the essential components of the alimentary tract, including its continuous muscular design from mouth to anus and related anatomical features. Perfect for students of anatomy and physiology to test their understanding.

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