Font Size
A
A
A

Anatomy of the Digestive System (cont.)

Small Intestine

Most digestion and absorption of food occurs in the small intestine. The small intestine is a narrow, twisting tube that occupies most of the lower abdomen between the stomach and the beginning of the large intestine. It extends about 20 feet in length. The small intestine consists of three parts: the duodenum (the C-shaped part), the jejunum (the coiled midsection), and the ileum (the last section).

The small intestine has two important functions.

  1. The digestive process is completed here by enzymes and other substances made by intestinal cells, the pancreas, and the liver. Glands in the intestine walls secrete enzymes that breakdown starches and sugars. The pancreas secretes enzymes into the small intestine that help breakdown carbohydrates, fats, and proteins. The liver produces bile, which is stored in the gallbladder. Bile helps to make fat molecules (which otherwise are not soluble in water) soluble, so they can be absorbed by the body.
  2. The small intestine absorbs the nutrients from the digestive process. The inner wall of the small intestine is covered by millions of tiny fingerlike projections called villi. The villi are covered with even tinier projections called microvilli. The combination of villi and microvilli increase the surface area of the small intestine greatly, allowing absorption of nutrients to occur. Undigested material travels next to the large intestine.
Medically Reviewed by a Doctor on 12/1/2014
Medical Author:

Must Read Articles Related to Anatomy of the Digestive System

Anatomy Involved in Crohn's Disease
Anatomy Involved in Crohn Disease The digestive system is made up of the digestive tract, which is a long series of organs, including the esophagus, the stomach, the small intestine, and the lar...learn more >>



Read What Your Physician is Reading on Medscape

Colon, Polyps »

A polyp is a small growth of tissue shaped like the head or stalk of a mushroom.

Read More on Medscape Reference »


Medical Dictionary