The large intestine, or colon, consists of three parts: the ascending colon, the transverse colon, and the descending colon. It ends in the rectum. The very bottom of the digestive system is called the anus. Here again, there are very important rings of muscle called the anal sphincter.

The purpose of the large bowel, is to re-absorb much of the water that was used in the digestion process and some of the substances that were used in digestion. The anus is the end of the large bowel, and excretes any unabsorbed food residue.