IV MOTILITY OFTHE SMALL INTESTINE
1 IV MOTILITY OF THE SMALL INTESTINE
Function of Intestinal Motility (I)To mix chyme with digestive secretion (2)To bring fresh chyme into contact with the absorptive surface of the microvilli (To propel chyme toward the colon
2 Function of Intestinal Motility (1)To mix chyme with digestive secretion (2)To bring fresh chyme into contact with the absorptive surface of the microvili (3)To propel chyme toward the colon
Contractions of Intestinal Smooth Museles Occur automatically in Slow waves response to endogenous 28 pacemaker activity Rhythm of contractions is mV paced by graded depolarizations called slow waves 5 sec Slow waves produced by interstitial cells of Cajal Slow waves spread from I smooth muscle cell to another through nexuses 3
3 Contractions of Intestinal Smooth Muscles • Occur automatically in response to endogenous pacemaker activity. • Rhythm of contractions is paced by graded depolarizations called slow waves. •Slow waves produced by interstitial cells of Cajal. •Slow waves spread from 1 smooth muscle cell to another through nexuses
Cells and Electrical Events inthe Muscularis Copyright e The MoGraw-Hill Companies, Inc. Permission required for reproduction or display. Structures Functions Production Interstitial of slow waves cells of Cajal Conduction of slow waves to smooth muscle Depolarization Smooth and opening of muscle Caz+ channels, cells production of action potentials Autonomic Neural input to ICC and smooth axon muscle
4 Cells and Electrical Events in the Muscularis Insert fig. 18.16
Stuart Ira Fox, Human Physiology, 6e. Copyright e 1999 The McGraw-Hill Companies, Inc. All rights reserved. Electrical Activity in Intestinal smooth muscle Pacesetter potential Membrane potential Smooth muscle contraction Tension 0421.PC
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