Digestive System A Processes Ingestion food in Movement

Digestive System A. Processes – Ingestion (food in), Movement, Digestion (chemical and mechanical), Absorption, Defecation B. Types C. D. 1. Chemical – breakdown of large carbohydrates, lipids and protein into simple molecules 2. Mechanical – chewing, muscular contraction http: //cache. eb. com/eb/imag e? id=8039&rend. Type. Id=4 http: //www. nlm. nih. gov/medline plus/ency/images/ency/fullsize/1 9823. jpg http: //biology. clc. uc. edu/gra phics/bio 104/glucose 1. jpg

C. Organization: Gastrointestinal Tract and Accessory Organs 1. GI Tract (Alimentary Canal) – mouth, pharynx, esophagus, stomach, small intestine, large intestine 2. Accessory Organs – teeth, tongue, salivary glands, liver, gall bladder, pancreas http: //visual. merriamwebster. com/images/hu manbeing/anatomy/digestivesystem. jpg

D. Histology 1. mucosa – inner lining – mucous membrane 2. submucosa – areolar connective tissue binds mucosa to muscle, contains blood and lymphatic tissue 3. muscularis – skeletal – mouth, pharynx, upper esophagus, (swallowing) smooth muscle – the rest of the tract 4. serosa – outermost layer, serous fluid allows for free gliding of the mesentery, omentum and falciform ligament http: //cache. eb. com/eb/image? id=74315&rend. Type. Id=4

E. Digestive Tract: Anatomy and Physiology F. G. H. 1. membrane Mouth – oral or buccal cavity a. Tongue – skeletal muscle covered with mucous Extrinsic muscles – outside and insert in, move tongue side to I. side and in and out J. Intrinsic muscles – inside, speech and swallowing K. L. b. Salivary glands - 3 pairs – parotid, submandibular, sublingual Saliva – 99. 5% H 2 O, . 5% solutes – lubrication and dissolving, Salivary Amylase under nervous control http: //academic. kellogg. cc. mi. us/herbran dsonc/bio 201_Mc. Kinley/f 264 a_salivary_glands_c. jpg

c. Teeth – located in bony sockets of maxilla and mandible - KNOW TYPES AND FUNCTIONS http: //www. medem. com/MEDEM /images/AMA/ama_preventive_o ralhealth_lev 20_theteeth_01. jpg http: //whyfiles. org/shorties/1 47 tooth/images/teeth. jpg http: //dentistsplans. com/images/health ytooth. jpg

d. Digestion in the mouth e. Mechanical – Mastication (chewing) f. Chemical – Salivary Amylase – starts breakdown of starch 2. Esophagus – lies behind the trachea 3. a. Function – transports food 4. b. Peristalsis – muscular movements (involuntary) to push food through esophagus 5. c. lower esophageal sphincter – prevents backflow of HCl (heartburn) http: //www. massgeneral. org/cancer/c rr/types/thoracic/illustrations/images/ esophagus_front. jpg

3. Stomach – J-shaped 4. a. Anatomy – cardia – superior opening 5. Fundus – up and to the left 6. Body – large central portion 7. Pyloris – narrow, inferior region b. Digestion MECHANICAL – mixing waves = Peristaltic movements every 15 -20 seconds, forms chyme CHEMICAL – Pepsin digests proteins, effective at p. H of 2 http: //www. nlm. nih. gov/medlineplus/en cy/images/ency/fullsize/19223. jpg Gastric Lipase breaks down large lipids (triglycerides) Controlled by nervous and hormonal mechanisms

c. Regulation of gastric emptying – Stomach empties all of contents into duodenum within 2 -6 hours d. Carbohydrates spend less time in stomach, proteins more e. Vomiting – forceful expulsion of contents from upper GI tract 4. Pancreas – behind stomach, secrete into duodenum through pancreatic duct 5. cells 6. a. Anatomy – Islets of Langerhans and Acini cells, 2 types of b. Pancreatic juices 7. EXOCRINE ENDOCRINE 8. Acini cells Islets of Produce mixture of digestive Glucagon 10. glucose) enzymes = pancreatic enzymes glycogen to 11. Multiple enzymes for digestion Insulin (transports 12. and of carbs, protein, fat glucose into cells 9. Langerhans (converts

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5. Liver – heaviest gland, supported by falciform ligament a. Functions: http: //www. best-vitamin-supplementsguide. com/images/liver. jpg b. Lobules consist of hepatic cells which produce bile c. Destroys worn out white and red blood cells, bacteria and other toxins d. b. Bile – yellow, brownish or olive green, p. H of 7. 6 -8. 6, aids in emulsification, conversion of fat into droplets, helps in absorption of fat 6. Gall bladder – concentrates and stores bile until needed by small intestine http: //www. nlm. nih. gov/medlineplu s/ency/images/ency/fullsize/1090. j pg

7. Small intestine – most digestion and absorption (90%) occurs here 8. 9. a. Anatomy – 21 ft long in cadaver, 10 ft long in living (muscle tone) Made up of duodenum, jejunum, ileum b. Adaptations - length, mucosa and submucosa are modified to increase digestion and absorption, villi and microvilli increase surface area, circular folds http: //www. cudahychamber. com/images /digestive_system. gif http: //instruct 1. cit. cornell. edu/courses/biog 105/page s/demos/105/unit 6/media/villus. structure. jpg

c. Digestion and absorption of major nutrients d. CARBOHYDRATES – maltase, sucrase and lactase break disaccharides into monosaccharides, absorbed as such e. PROTEINS – pepsin fragments proteins into peptides, Peptidase completes the task, absorbed as amino acids f. LIPIDS – occurs in small intestineby pancreatic lipase, absorbed as monoglycerides and fatty acids g. NUCLEIC ACIDS – done by intestinal and pancreatic juices http: //images. google. com/i mages? hl=en&rlz=1 T 4 DMUS _en. US 207&resnum=0 &q=nucleic%20 acids&um=1 &ie=UTF-8&sa=N&tab=wi http: //images. foodnetwork. com/webfood/ima ges/gethealthy/nutritionalallstars/Lean. Protei ns_header. jpg

8. Large Intestine – completion of absorption, makes vitamins, forms feces 9. a. Anatomy – 5 feet long, 2. 5 in in diameter, ileocecal sphincter, appendix, ascending, transverse, descending and sigmoid colon 10. b. Digestion, absorption, and feces formation – MECHANICAL – following meal chyme is forced into cecum, food intiates mass peristalsis – drives colon contents into the rectum – 3 or 4 times daily 11. 9. Disorders of the digestive system http: //immunesupportonline. co m/Images/Digestive%20 Syste m%20 Anatomy_files/Digestive %20 tract%20 annotated. jpg

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