Digestive System I with px

Digestive System I with px - Digestive System I Oral Cavity...

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Digestive System I: Oral Cavity and Associated Structures (Chapter 16; pg. 476 – 517) The Digestive System (alimentary canal): includes oral cavity, mouth, pharynx, esophagus, stomach, small and large intestines, rectum, anus and its associated glands (salivary glands, liver, and pancreas). The alimentary canal is physically and functionally external to the body. A. Alimentary Mucosa: 1. Function: a. Digestion 1. Enzymatic breakdown of food 2. Chewing 3. Positioning of food 4. Saliva dissolves food; enzymes 5. Skeletal/smooth muscle moves food toward and through tract; pulverizes and mixes 6. Glands add mucous, acid, enzymes 7. Bile acts as detergent; lipid digestion b. Absorption: mainly in intestine; absorption of nutrients in small intestine; absorption of water in large intestine. Enhanced by microvilli, villi, plicae circulares c. Excretion: bile into small intestine; feces d. Endocrine: enteroendocrine cells (DNES) e. Protection: lymphoid tissue; lysozymes; mucous; tight junctions; liver detoxification
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B. Oral Cavity: mouth and its contents 1. General histology: a. Mucosa 1. Masticatory mucosa: located on gingiva and hard palate; keratinized stratified squamous epithelium; lamina propria with vascular papillae and mucous glands; mucosa firmly adherent to underlying bone 2. Lining mucosa: located on lips, cheeks, alveolar mucosal surfaces, floor of mouth, inferior surface of tongue and soft palate. Usually unkeratinized stratified squamous epithelium; lamina propria has fewer and shorter papilla; submucosa with blood vessels and small salivary glands; skeletal muscle 2. Lip and Cheek (see lab manual, page 262-263)
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