gastrointestinal tract gastrointestinal tract the gastrointestinal tract (gi tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. the gi tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines. digestiondiagram of stomach, intestines and rectum in the average humandetailssystemdigestive systemidentifierslatintractus digestorius (mouth to anus),canalis alimentarius (esophagus to large intestine),canalis gastrointestinales stomach to large intestine)meshd041981anatomical terminology major parts of thegastrointestinal tract upper gastrointestinal tract mouth esophagus stomach duodenum lower gastrointestinal tract small intestine jejunum ileum large intestine sigmoid colon rectum anus