Small intestine

This digestive organ forms a tube that is over 5 metres in length and connects the stomach with the colon. It secretes the intestinal juice that contains the enzymes necessary for the transformation of chyme from the stomach into nutrients. Nutrients are absorbed by passing into the bloodstream to reach the various organs of the body. Chyme generally spends less than two hours in the small intestine, which is divided into three parts: the duodenum (which means "12 fingers long"), the jejunum ("empty stomach") and the ileum ("wound  up"). The duodenum, which is approximately 25cm long, is connected to the liver and the pancreas, which secrete bile and pancreatic juice into it respectively. The jejunum has many folds, reaching a total of 2.5 metres in length and is followed by the ileum which, when unfolded, is approximately 3.6 metres long and leads into the large intestine via the ileocecal valve. 

 

The total surface area of the small intestine amounts to some 200m², which is equivalent to the floorspace of a two-storey house.