Lecture 23 Study Questions PDF

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Lecture 23 Study Questions Big Picture: 1. What are some important big picture functions of the digestive system? 2. What are the two main divisions of the digestive system and the organs that compose them? The alimentary tract and the accessory organs. Alimentary tract= mouth, pharynx, esophagus, stomach, small and large intestine, rectum and anus. Accessory organs= salivary glands, gallbladder, liver, pancreas 3. What is the path of food through the GI tract? 4. What are the digestive functions of the oral cavity, salivary glands, teeth, tongue, pharynx, and esophagus?  Oral cavity: sensory analysis, mechanical digestion, lubrication, chemical digestion  Salivary glands: produce and secrete saliva  Teeth: cut up food  Tongue: pushed food to back of throat  Pharynx: portions passageways for both food and air  Esophagus: major function: propulsion. Minor function: secretion of mucous Details: 1. What are the functions of the digestive system? Ingestion, mixing and propelling, digestion, secretion, absorption, defecation Be sure that eventually you know where each of these may occur in the digestive system (in each organ). 2. How are intraperitoneal organs different from retroperitoneal? Intraperitoneal are organs inside the peritoneal cavity ( stomach, liver, jejunum, ileum, transverse colon, sigmoid colon) retroperitoneal organs are covered only in parietal peritoneum ( (suprarenal) adrenal glands, aorta, duodenum, ascending colon, descending colon pancreas, ureters, color, kidneys, esophagus, rectum) SAD PUCKER. How do nerves and vessels reach intraperitoneal organs? The ligaments, omenta, and mesenteries permit blood vessels, lymphatics and nerves to reach the viscera without piercing the peritoneum. What is a mesentery? They are two layered folds of peritoneum, which connect the parts of the intestine to the posterior abdominal wall. Do retroperitoneal organs have a mesentery? no 3. What are the four histological layers of the GI tract? Mucosa, submucosa, muscularis externa, serosa a. Which layers are involved in secretion of substances? mucosa b. Which layers are involved in propulsion of digestive products? Muscularis externa because its contains smooth muscle c. Which layers are involved in absorption of molecules? d. How are nerves integrated into these layers? Why are nerves present? e. Please eventually understand how the mucosa varies in the esophagus, stomach, small intestine, large intestine & rectum. Please also note that retroperitoneal organs have an adventitia, not a complete serosa, but intraperitoneal organs have a serosa (which is the visceral peritoneum). 4. What is peristalsis? Alternate waves of contraction and relaxation of muscles, moving the food down. What function does it serve? Propulsion, swallowing Why is segmentation important to digestive function? It’s the mechanical processing of food with no directional movement Are peristalsis & segmentation the same? no 5. What digestive activities occur in the oral cavity? Mechanical and chemical digestion How are the tongue, hard palate and teeth involved? Tongue is involved by mechanical processing manipulating, sensory analysis, and secretion. The hard palate is involved by providing a barrier to break the food down. The teeth break down the food. 6. What is saliva? Mainly water, ions, enzymes, antibodies, waste, proteins, cyanide, defensins a. Where is saliva produced? Oral cavity b. How does saliva contribute to chemical digestion? Moistens the food and contains enzymes c. What signals saliva production? Parasympathetic by chemo and mechanoreceptors. Is watery saliva can be triggered by thought, smells, eaten, or seen. d. What inhibits saliva production? Sympathetic, mucous- rich saliva.

7. Regarding teeth: a. Are the teeth living structures? Yes, they are bone like material called dentin, caped by enamelsupplied by blood vessels and nerves in root. b. What are the digestive functions of teeth & cheeks? To cut, tear, crush and grind food c. What are the crown, root, neck, root canal, dentin, enamel, pulp cavity, gingivae & periodontal ligament? 8. Regarding swallowing and the esophagus: a. What structure prevents food from entering the airway? epiglottis b. What is the most important digestive function of the esophagus? propulsion c. How does food move through the esophagus? Begins posterior to larynx, runs dorsal to trachea and heart. Joins stomach and cardiac sphincter. d. What is the epithelium of the esophagus? Stratified squamous epithelium. Why is this not a simple columnar epithelium? Because it doesn’t need as much protection and things are being absorbed here. e. Is swallowing voluntary, involuntary or both? both Clinical Correlation Questions: 1. Why can digestion occur in people with spinal cord injury that paralyzes skeletal muscle or transects the spinal cord? 2. Chemotherapy agents target rapidly dividing cellular populations (cancer) but also affect gut epithelial cells. What symptoms would you expect to find associated with this destruction in people undergoing chemotherapy treatment for cancer? 3. Why is enamel loss important?...