The colon is the last part of the digestive system. It extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which fermentation of unabsorbed material occurs.
Unlike the small intestine, the colon does not play a major role in absorption of foods and nutrients. However, the colon does absorb water, potassium and some fat soluble vitamins.
The colon consists of four sections:
Located on the right side of the abdomen, is about 25 cm long. It is the part of the colon from the cecum to the turn of the colon by the liver.
The transverse colon hangs off the stomach, attached to it by a wide band of tissue. On the posterior side, the transverse colon is connected to the posterior abdominal wall. Cancers form more frequently further along the large intestine as the contents become more solid (water is removed) in order to form feces.
The descending colon stores food that will be emptied into the rectum.
The Sigmoid Colon is the part of the large intestine after the descending colon and before the rectum. The walls of the sigmoid colon are muscular, and contract to increase the pressure inside the colon, causing the stool to move into the rectum.
FunctionThe large intestine comes after the small intestine in the digestive tract. The large intestine is mainly responsible for storing waste, reclaiming water, maintaining the water balance, absorbing some vitamins. By the time the chyme has reached this tube, most nutrients and 90% of the water have been absorbed by the body. As the chyme moves through the large intestine, most of the remaining water is removed, and the chyme and becomes feces. The stools become semi solid as they move along into the descending colon.
Most people can avoid problems in the colon simply by eating a diet which is high in fiber and fruits and low in lean meat.