Colon Function

Being the last part of the digestive system, colon performs some really important functions. This last portion of the human gastrointestinal tract is approximately 5 to 5.5 feet long with a diameter of about 2.5 inches. Colon is basically deals with the removal of the waste products of digestion or stool, reabsorption of water from the waste products and absorption of electrolytes and certain vitamins. Colon is also the site, where the intestinal flora, especially, the friendly bacteria reside and carry out fermentation of the undigested food material. So, colon is one of the most important part of the human digestive system.

Colon Structure and Location in the Body

Human and mammalian colon can be divided into four sections, ascending, transverse, descending and sigmoid colon. Colon is the portion of the large intestine that is located between the caecum and rectum. Caecum is the first portion of the large intestine, which connects the colon to the last part of the small intestine, i.e. ileum. Colon begins on the lower right side of the abdominal cavity, where the caecum ends. From this point, it ascends from the caecum to the level of liver or hepatic flexure. This portion is the first part of the colon, i.e. ascending colon, which is approximately 25 cm long.

At the hepatic flexure, the colon takes a sharp turn to the left and crosses the abdominal cavity. This portion of the colon is called transverse colon. At the level of the spleen, or the splenic flexure, the colon moves down to the left and this portion is known as the descending colon. The last part of the colon is sigmoid colon, which is the S-shaped portion that comes after the descending colon and before the rectum.

What is the Function of the Colon?

As has been mentioned above, the colon works as the organ for storing waste products, reabsorbing water from wastes and maintaining water balance in the body. Apart from these, it serves at the site for the growth of beneficial bacteria and other microorganisms, that help to ferment undigested and unabsorbed food material, and synthesize some vital nutrients like, folic acid. These friendly bacteria also help to check the growth of harmful bacteria, and maintain the pH balance in the body. Vital electrolytes and some vitamins, especially, vitamin B and vitamin K, which is required for blood coagulation is absorbed in this part of the large intestine.

However, its most crucial function is the elimination of toxic waste material in the form of stool or feces through the rectum. Its muscles contract in a wave-like manner, to pass the stool down the rectum. Generally, the waste material or stool is liquid, when it enters the first part of the colon. As the liquid waste material move through this organ, all excess water is absorbed from it and by the time the stool reaches the descending colon, it becomes semi-solid. In its descending part, the waste material is stored, until it is emptied into the rectum. Defecation takes place, when the muscles of the sigmoid colon contracts to increase the pressure inside the colon, so that the stool can move and enter the rectum.

The bulkier the stool is, the more easily it can be moved and expelled by the colon. The stool becomes bulkier, when it contains more fiber. This is the reason why, enough fiber rich foods needs to be included in the diet to ensure regular bowel movements. Usually, an individual can have two to three bowel movements in a day, if the colon is healthy and functioning properly. The bacteria in this organ break down the fiber for their nourishment, and in the process generate acetate, propionate and butyrate as by products, which in turn, nourish the cells lining the colon.

When the normal functions of this organ are disrupted, one can experience several health problems, mainly due to accumulation of the toxic waste material within the colon, and impairment of the absorption of some vital nutrients. Most often, it fails to function properly, when we do not follow a healthy lifestyle and diet. So, a balanced diet with lots of fruits and other fiber rich foods can prove immensely helpful in avoiding colon and large intestine problems and ensuring proper functioning of this part of the gastrointestinal tract.