PHGY 210 Lecture Notes - Lecture 3: Thoracic Cavity, Swallowing, Peristalsis
30 Sep 2020
School
Department
Course
Professor
Document Summary
If there was no ues, the air would be sucked into the esophagus which we don"t want to happen. Esophageal forces: gravity: minor importance; small effect for liquids. Plays no role for food and only minor effect for liquid because you don"t need gravity to swallow: peristalsis: esophageal contents carried toward stomach. A wave of contraction moving over the wall of the organ, narrowing the lumen and setting up a gradient of pressure favoring aboral (proximal to distal) movement. Contraction of the pharyngeal receptors activate the deglutition centre in the medulla which sends two vagal fibers to contact the esophagus. Vagus somatic fibres: innervate the striated portion musculature to cause the peristaltic wave here. Vagus autonomic fibres: innervate the more distal parts. This happens in a smoothly propagated fashion so how is this coordinated: sequential, proximal to distal activation: wave of activity in striatal muscle, the vagus somatic fibers reach the musculature in a sequential fashion.
