Brain–Gut Axis and Regional Gastrointestinal Tract Motility

Abstract

This chapter expands on the description of the brain–gut axis, introduced in Chaps. 1 and 2, relative to its role in the coordination of GI motility. Digestion involving the oral cavity and esophagus is covered by discussion of the mechanism of mastication and the process of swallowing in terms of the interactions of the upper esophageal sphincter (UES), primary and secondary peristalsis, and the lower esophageal sphincter (LES). The principles behind stimulation and inhibition of gastric motility are outlined and the role of extrinsic control is illustrated. Small bowel motility is considered with respect to the roles of segmentation and peristaltic contractions. With respect to the ileosphincteric valve the roles of ileal distention and colonic distention are discussed. Finally, the mechanisms and functions of colonic peristalsis, haustrations, and mass movements are considered.