A Summary of the Human Digestive System

by, Mark

The Small Intestine

Facts for the Small Intestine

The small intestine measures eighteen to twenty-three feet in the average adult. This makes it about four times longer than the person is tall.

The intestines process about 2.5 gallons of food, liquids and bodily waste every day.

In one square inch of small intestine, there are about 20,000 villi and ten billion microvilli.

The small intestine makes waves, which move the food forward. These are usually weak and infrequent and allow the food to stay in one place until the nutrients can be absorbed.

If a toxic substance enters the small intestine, these movements may be strong and rapid to expel the poisons quickly.

Information on the Small Intestine

There are three sections of the Small Intestine. The duodenum, which is where the chemicals used for digestion are received as well as some digested food from the stomach. The jejunum is where most of the nutrients are absorbed into the blood stream. Finally, the ileum is where the remaining nutrients are absorbed before it passes into the large intestine. There is a large number of intestinal cells, which look like small folds. Each of these cells contain thousands of tiny finger-like projections called "villi." In order to stir up liquefied food and remove nutrients, the villi sway repeatedly. The muscles which surround this tube contract about seven to twelve times a minute to move the food back and forth.

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Last Updated On: July 24, 2000