Digestive system. Artwork showing a healthy human digestive system. Food enters the stomach (top right) where it is stored and partially broken down ready for digestion in the small intestine (smooth tube below). Food residue then passes into the colon, the main part of the large intestine (ribbed), a muscular tract in which excess water is absorbed. The finger-like appendix is seen in the first section of the colon at lower left. Faeces are stored in the rectum (lower centre), at the end of the large intestine, until they are expelled.