Six metres of gut
After the duodenum the small intestine coils in loops through the middle and lower abdomen, framed by the large intestine. Its first two fifths are the jejunum, wider and with a thicker wall, and the last three fifths the ileum. Measured after death the whole is about six metres long, and in a living person less.
The small intestine: duodenum, jejunum and ileum, framed by the large intestine, OpenStax Anatomy and PhysiologyWikimedia Commons, OpenStax College, CC BY 3.0 (2417 Small IntestineN.jpg)
Here digestion is finished and nearly all the food is absorbed. Rings of muscle contract in segments that churn the chyme against the wall, and slow waves push it on at about a centimetre a minute. A meal takes three to five hours to travel from the pylorus to the large intestine.
Sources
- Susan Standring (ed.), Gray's Anatomy, 42nd ed. (2020), chapter on the small intestine.
- Arthur Guyton and John Hall, Textbook of Medical Physiology, 13th ed. (2016), ch. 64 and 66.
Prev: Bile and the gallbladderNext: Folds and villi