4.1 Gastrointestinal System Anatomy & General Principles Quiz
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Questions and Answers

Which layer of tissue in the GI tract is responsible for secretion and absorption processes?

  • Submucosa
  • Muscularis externa
  • Mucosa (correct)
  • Serosa
  • What is the primary stimulus for the secretion of GI hormones?

  • Presence of fatty foods in the diet
  • Increase in blood glucose levels
  • Acidic pH in the stomach
  • Distension of the GI wall (correct)
  • Which type of movement in the GI tract involves mixing and churning of the luminal contents?

  • Segmentation (correct)
  • Mass movement
  • Peristalsis
  • Migrating motor complex
  • In the splanchnic circulation, blood from the GI tract drains into which major vessel?

    <p>Hepatic portal vein</p> Signup and view all the answers

    Which neurological component provides parasympathetic innervation to the GI tract?

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

    What specialized structure in the intestine is responsible for absorbing chylomicrons?

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

    What is the main function of the tunica mucosa in the digestive system?

    <p>Secretion, absorption, or hormone production</p> Signup and view all the answers

    Which part of the small intestine has the highest surface area increase due to its structures?

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

    What regulates the opening and closing of the ileocecal valve?

    <p>Increased ileal pressure</p> Signup and view all the answers

    What is the structure that extends from the cecum and opens into the ileum?

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

    Which region of the colon extends up the right side of the abdominal cavity to the liver?

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

    What is the main purpose of the plicae circulares in the small intestine?

    <p>Increase surface area for absorption</p> Signup and view all the answers

    Which region of the gastrointestinal tract extends from the splenic flexure of the colon to the rectum?

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

    What is the terminal region of the pylorus that connects to the duodenum known as?

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

    Which part of the small intestine is mostly responsible for absorption?

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

    Which section of the large intestine is located just below the body of the stomach?

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

    What structures are included in the foregut region of the gastrointestinal tract?

    <p>Esophagus, Stomach, Part of Duodenum</p> Signup and view all the answers

    Which part of the stomach functions as a blind sac on the left side of the stomach?

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

    What is the primary arterial supply to the midgut region of the gastrointestinal system?

    <p>Superior Mesenteric Artery</p> Signup and view all the answers

    What is the role of VIP in the gastrointestinal system?

    <p>Regulates smooth muscle contraction.</p> Signup and view all the answers

    Which nervous system is referred to as the 'little brain' for its control over GI function?

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

    What effect does parasympathetic activity have on intestinal smooth muscle?

    <p>Increases activity.</p> Signup and view all the answers

    Which plexus controls local intestinal secretion, absorption, and mucosal infoldings?

    <p>Myenteric plexus.</p> Signup and view all the answers

    What is the primary function of the submucosal plexus in the ENS?

    <p>Regulates local intestinal secretion and absorption.</p> Signup and view all the answers

    How does sympathetic activity affect intestinal smooth muscle?

    <p>Decreases activity.</p> Signup and view all the answers

    What is the main purpose of splanchnic circulation in the GI system?

    <p>To remove bacteria and absorb carbohydrates and protein</p> Signup and view all the answers

    How are fats absorbed from the intestinal tract different from other nutrients in terms of circulation?

    <p>Fats are absorbed into lacteals and conducted to systemic circulation</p> Signup and view all the answers

    What happens when there is sympathetic stimulation in terms of GI blood flow?

    <p>Arteriolar vasoconstriction leads to decreased blood flow</p> Signup and view all the answers

    How does autoregulatory escape mechanism help during circulatory shock?

    <p>It maintains normal blood flow despite ischemia conditions</p> Signup and view all the answers

    What is the main consequence of countercurrent blood flow in the villi?

    <p>Causing ischemia at the tips of the villi</p> Signup and view all the answers

    In disease states, why can shunting of oxygen across the villus be harmful?

    <p>It leads to reduced oxygen levels at the villus tips causing ischemia</p> Signup and view all the answers

    Study Notes

    Gastrointestinal System Anatomy

    • The GI system consists of the oral cavity, pharynx, esophagus, stomach, small intestine, and large intestine, along with associated glands.
    • The GI tract is a portal for nutrient and water absorption, and is also known as the alimentary canal or gut tube.

    Tissue Layers (Tunics)

    • The GI tract has four major layers (tunics) of tissue: tunica mucosa, submucosa, tunica muscularis, and tunica serosa.
    • Tunica mucosa is the innermost lining of the lumen of the digestive tube and varies the most among the four tunics.
    • It is composed of specialized epithelium that accomplishes regional digestive tasks such as secretion, absorption, or hormone production.

    General Principles of Gastrointestinal Motility

    • There are two types of electrical waves that excite GI smooth muscle: slow waves and spike potentials.
    • Slow waves are rhythmic, spontaneous, and omnipresent, and they do not cause contraction of smooth muscle.
    • Spike potentials are superimposed on slow waves and cause contraction of smooth muscle.

    Neural Control of Gastrointestinal Function

    • The GI tract has dual innervation provided by the Enteric Nervous System (ENS) and the Autonomic Nervous System (ANS).
    • The ENS is an intrinsic nervous system that can function autonomously and is composed of the myenteric plexus and the submucosal plexus.
    • The ANS is an extrinsic nervous system that provides parasympathetic and sympathetic innervation to the GI tract.

    Hormonal Control of Gastrointestinal Function

    • There are five major GI hormones: gastrin, secretin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), and vasoactive intestinal peptide (VIP).
    • Each hormone has a specific stimulus for secretion, site of secretion, and action.

    Functional Movements in the GI Tract

    • There are two types of functional movements in the GI tract: segmentation and peristalsis.
    • Segmentation is the mixing of food with digestive enzymes and is characterized by rhythmic, simultaneous contractions and relaxations of the circular muscle layer.
    • Peristalsis is the propulsion of food through the GI tract and is characterized by a wave of contraction that moves along the longitudinal muscle layer.

    GI Blood Flow - Splanchnic Circulation

    • Splanchnic circulation is the blood flow to the GI system, which includes the gut, spleen, pancreas, and liver.
    • Blood flows through the gut, spleen, pancreas, and then into the liver via the portal vein, before entering the general circulation.
    • The liver sinusoids remove bacteria, absorb carbohydrates and protein, and process fats absorbed from the intestinal tract.

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    Description

    Test your knowledge on the gross anatomy, tissue layers, motility, nervous and hormonal control, functional movements, blood flow, and pathophysiology of the gastrointestinal system with this quiz.

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