04_Lecture Notes_NPB 114

Mechanism not completely clear iii wave

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Unformatted text preview: s 1. About 20 cm 2. Normally contracted 3. Upper 1/3 is skeletal muscle that’s not voluntarily controlled 4. Middle 1/3 a. Mix 5. Bottom 1/3 a. Smooth muscle 6. In some humans sphincters tones are lost ii. In other animals 1. Pigs = entirely skeletal 7 Lecture 4 July 5, 2012 Salivary Secretions – Pharynx and Esophagus – Swallowing III. Lecture 4 Swallowing a. Background i. Need peristalsis to move anything ii. Broken down into 3 phases 1. Oral Phase 2. Pharangeal Phase a. Sometimes Oral and Pharangeal phase not separated 3. Esophageal b. Oral Phase i. Voluntary initation 1. Chewing 2. Separate a small bolus of food a. Generally will not swallow the entire thing at once 3. Push up towards roof of the mouth, typically with the tip of your tongue a. Roof of the mouth + decision to swallow signals brain for the swallow reflux response ii. Involuntary phase probably coming from “swallowing centers” of the brain stem 1. Mechanism not completely clear iii. Wave (peristalsis ­like) of contraction 1. Tip of tongue pushes bolus of food up 2. Soft palate contracts a. Blocks of nasopharynx to keep food stuff from it 3. Bolus push into back wall of pharynx iv. Cessation of breathing 1. Serve as a protective function c. Pharangeal phase i. Movement of laryngeal region 1. In response to musculature of larynx...
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This note was uploaded on 06/12/2013 for the course NPB 114 taught by Professor Bautista during the Summer '08 term at UC Davis.

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