Gastrointestinal tract

Last revised by Craig Hacking on 1 Sep 2021

The gastrointestinal (GI) tract (TA: systema digestorium) includes any part of the oral cavity, oropharynx, hypopharynxesophagus, stomach, small bowel, colon, appendix, rectum and anal canal


The terms gastrointestinal system, alimentary canal, digestive system and digestive tract may be used as synonyms for the gastrointestinal tract in its entirety. However, the "digestive tract" is sometimes used to refer to the esophagus to the rectum only; with the oral cavity, oropharynx and hypopharynx excluded. Occasionally, the gastrointestinal tract is used in a more pedantic sense to refer to the stomach ("gastro-") and intestines only.

The gastrointestinal tract may itself be subdivided into the upper and lower gastrointestinal tracts. The upper gastrointestinal tract usually refers to the structures from the mouth to the duodenum, whilst the lower gastrointestinal tract refers to all structures distal to the duodenojejunal flexure, i.e. small and large bowels to the anal verge

The non-qualified term bowel , a.k.a. intestines or gut, is used to refer to the combination of the small bowel (small intestines) and large bowel (large intestines). It therefore encompasses the GI tract from the start of the duodenum (gastroduodenal junction) to the anus. The vermiform appendix is usually considered to be part of the large bowel, and hence the lower gastrointestinal tract.

See also

ADVERTISEMENT: Supporters see fewer/no ads