Unit 4 Lecture Notes.docx - Chapter 25 The Digestive System(25.1-25.7 1 Digestive Function a Ingestion b Digestion c Absorption d Defecation 2

Unit 4 Lecture Notes.docx - Chapter 25 The Digestive...

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Chapter 25: The Digestive System (25.1-25.7) 1.Digestive Function a.Ingestionb.Digestionc.Absorptiond.Defecation 2.Microscopic Anatomy (Deep Superficial) 3. Enteric Nervous System a. Esophagus, stomach. Intestines i. Motility, secretion, and blood flow b. Nerve Plexuses i. Submucosal Plexus 1. Secretory Activity ii. Myenteric Plexus 1. Muscularis externa 2. GI tract motility 4. Peritoneum a. Serous Membrane i. Mesenteries 1. Double layer a. Dorsal b. Ventral i. Greater omentum ii. Lesser omentum 2. Functions a. Routes for nerves, lymphatics/blood vessels b. Holds organs c. Stores fat 5. Digestive Tract Regulation a. Short vs. Long Reflexes i. Short Reflexes (Myenteric) 1. Intrinsic 2. Stimulates muscularis externa
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a. Response to stretching or chemicals ii. Long Reflexes (Vasovagal) 1. Extrinsic 2. Autonomic NS control a. Parasympathetic fibers of vagus nerve b. Stimulates motility and secretion 6. Oral Cavity a. Buccal cavity b. Functions i. Ingestion ii. Mastication iii. Chemical Digestion iv. Swallowing c. Salivary glands 7. Esophagus a. Long muscular tube i. Pharnyx to stomach 1. Mucus for lubrication b. Cardiac orfice i. Cardiac sphincter 8.Deglutition 9. Stomach a. Muscularis externa i. 3 layers b. Muscosa i. Gastric pits 1. Tubular glands 2. Based on location 10. Mucosal Barrier 1. Bicarbonate-rich mucus ii. Epithelial cell replacement 1. Every 3 – 6 days iii. Tight junctions 1. Prevents gastric juice leaking 11. Gastric Pits a.Mucous cellsi.Mucus
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b.Parietal cellsi.Hydrochloric acid 1. Functions a. Activates enzymes b. Liquefies food c. Converts iron d. Nonspecific resistance 2. Bicarbonate reaction a. Carbonic anhydrase 3. Alkaline tide a. High blood pH during digestion c. Chief cells i. Pepsinogen 1. Zymogens a. Inactive digestive enzymes 2. Activated by HCl a. Forms Pepsin i. Protein digestion 12. Regulation of Gastric Function a. NS and ES collaboration b. Three phases (know details) i. Cephalic 1. Controlled by brain ii. Gastric 1. Controlled by stomach iii. Intestinal 1. Controlled by small intestine
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  • Summer '17
  • Kyle Harris
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