ABSTRACT
As with the rest of the gut, the large intestine has muscular walls. In the large intestine, the longitudinal smooth muscle layer of muscularis externa is gathered together into three bands known as the taeniae coli. When these contract, the large intestine becomes bunched up. When the circular smooth muscle layer of muscularis externa contracts, this produces haustrations. Large intestinal motility takes two main forms: phasic contractions like those mentioned above that do not propel feces along the colon, but squeeze the colon contents; and mass propulsive movements that are designed to move feces toward the rectum for defecation. Control of motility in the large intestine is not particularly well understood, but mass propulsive movements tend to follow a meal; neural and hormonal reflexes such as the gastroileal reflex and the gastocolic reflex are important.
