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12 Cards in this Set
- Front
- Back
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Functions |
1. ingestion 2. digestion 3. absorption 4. defecation |
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Processes |
1. motility 2. secretion 3. membrane transport |
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I. Stages of Digestion |
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mechanical digestion |
physical breakdown of food into smaller particles; increases surface area for digestion |
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chemical digestion |
hydrolytic reactions that break macromolecules down into their monomers (residues), e.g., polysaccharides into monosaccharides, fats into fatty acids and glycerol, proteins into amino acids |
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II. Alimentary Canal |
"food tube" mouth----> anus
1. mucosa - epithelial tissue/lining 2. pH 3. musculature |
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Mouth (oral cavity, buccal cavity ) |
*labial frenulum *vestibule *tongue lingual papillae (between these are tastebuds) *hard and soft palate *teeth (incisors, canines, premolars, molars) (32 total, 16 in mandible, 16 in maxilla) *salivary glands -intrinsic - in the tongue, lips, inside of cheeks, small amount of saliva secreted - extrinsic - (3 pair) 1) parotid 2)submandibular gland 3)sublingual gland *saliva - 97% to 99.5% water; appox 7.0 pH - salivary amylase - starch --->oligosaccharides - lingual lipase - activated in stomach - mucus - lysozyme - non-specific immunity - immunoglobulin A - electrolytes |
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pharynx |
deep layer of longitudinal skeletal muscle; superficial layer of circular muscle divided into superior, middle, inferior constrictors |
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esophagus (straight muscular tube that conveys food to the stomach) |
*mucosa - non-keratinizing stratified squamous *submucosa *muscularis externa - inner circular muscle layer, outer longitudinal layer = peristalisis *adventitia or serosa (former above the diaphragm) *lower esophageal sphincter helps to prevent regurgitation of stomach contents |
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stomach |
*lesser and greater curvatures *cardiac region, fundus, corpus (body), pyloric region *stomach wall has layers similar to those of esophagus *rugae - longitudinal winkles in stomach lining; allows stomach to stretch w/o ripping *gastric secretions *mucosa - columnar epithelial with goblets *pH appox <2 *musculature - circular, longitudinal, and oblique layers of smooth muscle *gastric secretions - HCl - intrinsic factor - absorption of vitamin B12 - pepsin - digestion of proteins - gastric lipase and rennin - various chemical messengers, e.g., gastrin, serotonin, histamine, somatostation - chyme - partially digested food in stomach and small intestine |
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small intestine (all absorption of nutrients occurs here!! all chemical digestion completed here!) |
* duodenum (1st 10 inches), jejunum (next 8 feet), and ileum (last 12 feet) * functions: most digestion, almost all absorption of nutrients *intestinal villi - increase surface area *mucosa - columnar w/goblets *pH approx 8 * musculature - circular and longitudinal layers of smooth muscle |
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large intestine |
*cecum and vermiform appendix, ascending colon, transverse colon, descending colon, sigmoid colon, rectum *functions: bacterial flora produce certain vitamins; **reabsorption of water and electrolytes, storage of feces, stretching of rectum stimulates defecation reflex |
