Small intestine

Small intestine
Small intestine and surrounding structures
Details
Part of	Gastrointestinal tract
System	Digestive system
Artery	Superior mesenteric artery, jejunal arteries, ileal arteries
Vein	Hepatic portal vein, superior mesenteric vein
Nerve	Celiac ganglia, vagus[1]
Lymph	Intestinal lymph trunk
Identifiers
Latin	intestinum tenue
MeSH	D007421
TA98	A05.6.01.001
TA2	2933
FMA	7200
Anatomical terminology [edit on Wikidata]

Major parts of the
Gastrointestinal tract
Upper gastrointestinal tract Mouth Pharynx Esophagus Stomach Duodenum
Lower gastrointestinal tract Small intestine Jejunum Ileum Large intestine Cecum Appendix Ascending colon Transverse colon Descending colon Sigmoid colon Rectum Anus
See also Gastrointestinal wall Human digestive system Anatomical terminology Outline of anatomy
v t e

The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about 5.5 metres (18 feet) long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter.

The small intestine has three distinct regions – the duodenum, jejunum, and ileum. The duodenum, the shortest, is where preparation for absorption through small finger-like protrusions called villi begins.^[2] The jejunum is specialized for the absorption through its lining by enterocytes: small nutrient particles which have been previously digested by enzymes in the duodenum. The main function of the ileum is to absorb vitamin B₁₂, bile salts, and whatever products of digestion that were not absorbed by the jejunum.