PHSI 208 Lecture Notes - Lecture 5: Motilin, Bile Acid, Brush Border
Document Summary
Know the regulation of small intestinal motility patterns. Know the contribution of pancreatic and biliary secretions to digestion and absorption of nutrients. 12 feet of tubing in a living person, with a diameter of 1 inch. It is broken down into 3 regions, each of which have their own special action. The three regions are the duodenum, jejunum, and ileum. Segmentation contractions slowly mix and propel chyme with oscillating, ring like contractions. These contractions do not sweep the length like peristaltic waves. Initiated by pacesetter sells, segmentation contractions are increased by distension, the hormone gastrin released from the stomach, and extrinsic nerve activity (parasympathetic). The migrating motility complex starts when most of the meal is already absorbed, with the release of the small intestinal hormone motilin. Strong repetitive peristaltic waves occur from the stomach to the end of the small intestine. This sweeps the remaining contents towards the large intestine (colon).
