Large intestine

The large intestine reabsorbs water from the undigested food material and processes waste material. The main functions of the colon are to extract water and mineral salts from undigested food, and to store waste material. It is also inhabited by microorganisms that break down proteins into amino acids and amino acids into smaller components producing vitamin K and some B vitamins in the process.

The large intestine of a human is much smaller in length compared to the small intestine but larger in diameter. It has three parts: the cecum, the colon, and the rectum.

Figure 1: The vermiform (1), “worm-like,” appendix can be found right where the cecum (2) joins the ileum to the colon; the receiving organ for waste matter. The colon is home to many bacteria or “intestinal flora” that aid in the digestive processes. The colon can be divided into four regions, the ascending colon (3), the transverse colon (4), the descending colon (5) and the sigmoid colon (6). The rectum (7) is the terminal end of the large intestine and its primary role is to store the feces. The anus (8) is an opening at the far-end of the digestive tract and is the exit point for the waste material.