Journal of Clinical Investigation. Scandinavian Journal of Gastroenterology. Wikimedia Commons has media related to Gastrointestinal tract and Digestive system. Ferkin Food in the GI tract is called a bolus ball of food from the mouth down to the Fermiin. Upon dissectionthe duodenum may appear to be a unified organ, but it is divided into four segments based upon function, location, and internal anatomy. See also Gastrointestinal wall Anatomical terminology Outline of anatomy. Microsoft Academic 2 3 4. The main function of the large intestine is to absorb water. Ileocecal valve Peyer's patches Microfold cell. Bibcode San Fermin Gif NatCo.