PHGY 210 Lecture Notes - Lecture 18: Sphincter, Peristalsis, Swallowing
25 Feb 2013
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Document Summary
Peristalsis is a wave of contraction moving over the wall of the organ that is a continuous narrowing process that pressure food away from the mouth. Each time we swallow, we have 1 primary peristaltic wave, which takes 8-10 seconds to travel down the entirety of the esophagus. This is a part of the deglutition reflex. Pharyngeal receptors send signal to the deglutition centre, which then uses the vagus somatic efferent fibres to the striated muscle and the autonomic fibres of the vagus to the smooth muscle. The activation of the striated muscle is made in such a way that the propagation is timed perfectly. The smooth muscles are activated simultaneously, but react slightly differently due to distance. Innervation must at least reach the somatic striated fibres to have some sort of a peristalsis. The autonomic system, even when cut, will be overridden by the interlinked system of ganglion so long as the first of the smooth muscle is innervated.
