Colonic Transit and Motility

Abstract

The upper gastrointestinal tract transports food that has been eaten allowing digestion and ultimately absorption. The colon in humans has a storage and evacuation function and conserves fluid and electrolytes. In some mammals, i.e. the horse and the rabbit, the colon has a major function in the absorption of nutrients. The sphincters, placed at the junction between different parts of the gut, are specialized areas of smooth muscle, which regulate the forward and backward movement of intestinal contents. The ileocecal valve maintains a lower bacterial count in the small intestine by decreasing reflux of colonic contents into the ileum. The anal sphincter maintains contents in the colon until an appropriate time for expulsion.