Module 7: Figure small intestine

Small intestine neural and endocrine control systems.

Control of fluid secretion by the small intestine is controlled by a combination of neural and endocrine systems. The vagus and sympathetic inputs interact with the myenteric and submucous neural networks that send postganglionic endings to release vasoactive intestinal polypeptide (VIP) and acetylcholine (ACh) on to the surface of the intestinal cells. Enterochromaffin cells in the intestinal epithelium release 5-hydroxytryptamine (5-HT), which has a number of functions. L cells release various gut hormones such as peptide YY (PYY) and glucagon-like peptide 1 (GLP-1). See the text for further details.