GI Motility - Dr Kennon M Garrett GASTROINTESTINAL MOTILITY...

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Dr. Kennon M. Garrett GI-11 GASTROINTESTINAL MOTILITY Learning Objectives 1. List the functions of mastication. 2. List the events that occur during swallowing and movement of material down the esophagus. 3. Describe the motility in the different parts of the stomach. 4. Describe the regulation of motility in the stomach. 5. Describe the regulation of gastric emptying. 6. List the events in vomiting. 7. Describe the types of motility and reflexes in the small and large intestine. 8. List the activities and function of the migrating motility complex. 9. List the events during defecation.
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Dr. Kennon M. Garrett GI-12 I. Mastication (chewing) Functions: 1. mixes ingested material with saliva and lubricates to make it easier to swallow 2. breaks up large solids into sizes easier to swallow 3. begins digestion of starches with amylase in saliva II. Deglutition (swallowing) Functions: convey ingested material from the oral cavity to the stomach A. Oropharyngeal phase 1. Initiation - wave like contraction of tongue propels bolus to oropharynx - stimulation of pressure receptors and initiation of swallowing reflex 2. Oropharyngeal phase of swallowing reflex - Inhibition of respiration - Closure of air passageways - sequential contraction of pharyngeal muscles propels bolus toward esophagus Fig. 15-15 Movement of food through mouth and pharynx during swallowing.
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Dr. Kennon M. Garrett GI-13 3. Relaxation of upper esophageal sphincter (UES). UES is normally closed. UES relaxes during oropharyngeal phase of swallowing to allow the bolus to pass from the oropharynx into the esophagus and then closes. The UES acts to minimize reflux from esophagus into pharynx. B. Esophageal phase 1. Primary peristalsis - initiated by swallowing. A ring of smooth muscle constricts proximal to the bolus. The contraction ring propagates distally propelling the bolus toward the stomach. 2. Lower esophageal sphincter (LES). The LES is closed at rest and acts to minimize reflux of gastric contents into the esophagus. The LES relaxes to allow the bolus to pass into the stomach. 3. Secondary peristalsis - initiated by distention. Once initiated, it proceeds like primary peristalsis. Secondary peristalsis functions to remove material left behind by an ineffective primary peristaltic contraction and to return material refluxed up into the esophagus from the stomach. Primary peristalsis in the esophagus during swallowing
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Dr. Kennon M. Garrett GI-14 4. Lower esophageal sphincter (LES) and heartburn a. Increased intra-abdominal pressure - increased LES tone b. Ethanol, chocolate and peppermint - decreased LES tone c. Progesterone - decreased LES tone III. Gastric motility Functions of stomach: store ingested material, convert ingested material to chyme,
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This note was uploaded on 10/01/2011 for the course PSYO 5016 taught by Professor Staff during the Fall '11 term at The University of Oklahoma.

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GI Motility - Dr Kennon M Garrett GASTROINTESTINAL MOTILITY...

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