Colon

The large intestine or colon lies in a square position in the abdomen beginning at the lowest part of the right slide, and ascending up to the rib margin (ascending colon), then crossing to the left (transverse colon) and down the left side (descending colon).

Here it makes a twisted turn in the pelvis (sigmoid flexure), then ends in the rectum and anus. It is about 5 feet long and is a much wider tube than the small intestine. The appendix is attached to its pouch portion (cecum) on the right.

Most of the food is digested and absorbed in the small intestine. Whatever remains enters the colon in liquid form.The colon has no digestive juices but it secretes an alkaline mucus which encourages the growth of fermentative bacteria (acidophilus) these break up the undigested tough portion (cellulose) of carbohydrate foods.

By subjecting this by product of digestion to a prolonged churning, the first half of the colon absorbs whatever nourishment remains in the mass as well as all the moisture in it.

That is why the final portion to be expelled is often so dry.The action of the colon on the remains of the food digested in the stomach and small intestine takes about 20 hours.This comes to about three times as long as the period of digestion in the stomach and small intestine