The Small Intestine

The small intestine consists of about 9 feet of inch tubing coiled in the abdomen. This tubing connects the stomach to the large intestine. The small intestine does most of the digestion and absorption of food occurs.

Food passes into the small intestine from the stomach by entering the duodenum. The duodenum is the smallest segment of the intestine, just eight inches long. Food goes through the small intestine by weak waves of motion that pushes the food toward the large intestine.

The other two segments of the small intestine are the 3 feet long jejunum and it connects the duodenum to the ileum, the final 3 feet of the small intestine. The small intestine interior has many folds. Along the surfaces of these folds are tiny finger-like projections called villi.

Villi of the intestine move back and forth, like thousands of tiny tentacles, passing through the food as it moves along the intestinal tract. The villi play an important role in the absorption of food from the small intestine.

Through the center of each villi is one or more fine white vessels called lacteals which are part of the lymphatic system. Their principal function is probably the absorption of fat. As food passes through the small intestine, it is taken up, or absorbed, by structures in the wall of the intestines, especially by the villi, and is then secreted into the lacteals. Some of the digested food is absorbed by the numerous blood vessels that line the villi. Thus digested food directly enters the bloodstream.

As digestion progresses in the small intestine, portions of food are moving in large quantities into the capillaries of the intestinal villi. Blood from the intestines containing these products of digestion is collected in the portal vein, which is connected to the liver.

The liver is known as CHECK POST and removes the excess glucose from the blood (glucose being one of the end-products of digestion) and stores it as glycogen that is used later in normalizing the blood-sugar level and for supplying energy. It also attempts to detoxify harmful elements in the food such as pesticides, microorganisms etc and regulates the level of nutrients available to the body.

The bulk that remains behind after the vital elements are extracted in the intestine and sent to the liver is then pushed down toward the large intestine. Normally, most of the contents of the intestines have been absorbed by the time the food reaches the middle of the jejunum segment of the intestine.

NOTE - The tone and motility of the small intestine is increased by foods served at room temperature, fibrous foods, and high-carbohydrate, low-fat foods. Movement is slowed by cold, dry, and high-fat foods.

Go to Top

<< Back to Diet Main Page