Title: Small Intestine: Anatomy, Function, and Treatment
Headings: The Anatomy of the Small Intestine
The Anatomy of the Small Intestine
The largest digestive organ breaks down food and absorbs nutrients
Anatomy
The Mesentery
The Lymph System and the Small Intestine
Location
Anatomical Variations
Function
Absorption of Nutrients
The Lining of the Small Intestine
The Enteric Nervous System
Associated Conditions
Treatment
Tests

Content: 1 ﻿ The reason it is referred to as the “small” intestine, is because its lumen (opening) is smaller in diameter (at approximately 2.5 centimeters or 0.98 inches) than the large intestine ( colon ). The primary function of the small intestine is to break down and absorb ingested nutrients while mixing and moving the intestinal contents (consisting of gastric juices and partly digested food) along the digestive tract into the colon. magicmine/iStock/Getty Images
Anatomy
The small intestine is made up of thee sections, including the duodenum, the jejunum and the ileum. On its proximal (near) end, the small intestine—beginning with the duodenum—connects to the stomach. On its distal (far) end, the ileum—the last segment of the small intestine—connects to the large intestine (colon). The jejunum lies between the duodenum and the ileum. The anatomy of the three segments of the small intestine includes: The duodenum, the smallest segment of the small intestine, measuring only 10 to 15 inches in length. The duodenum begins where the stomach ends at the pylorus (the valve that opens and closes, allowing food to pass from the stomach into the small intestine). Next, the duodenum curves around the pancreas and ends in the area of the upper left quadrant of the abdomen, where it connects with the jejunum.