PLN 103 Lecture Notes - Lecture 4: Circular Folds, Common Bile Duct, Pancreatic Juice
13 Dec 2016
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Document Summary
Pln week 4 digestive system part ii. One extra layer for strength for gastric motility. Unique type of peristalsis in more then one direction to break down more throughouly. Pressure remains constant until it reaches 1l. Anticipation of when food enters or is about to and start relaxing. Coordinated by swallowing centre in brain stem. Stomach dilates from gastric filling (stretch receptors to start with mechanical) Local reflexes involving nitric oxide which is more systemic and local (vasodilator) Meal peristalsis at lower esophageal sphincter (by stomach) Contractions get stronger when it reaches pylorus because muscles are thicker. Pylorus holds 30ml of chime (each wave moves 3ml rest goes back into stomach for more mixing) Set the rate of contractions but do not initiate contractions. Depolarization waves are generated and enhanced by neural and hormonal factors in the longitudinal smooth muscle layer. Distension of stomach stretch receptors & gastric secreting cells gastric motility.
