 Gastrointestinal tract. The gastrointestinal tract. Digestive tract. Digestional tract. GI tract. Gut. Gut. For alimentary kindail is an organ system within humans and other animals which takes in food. Digests it to extract and absorb energy and nutrients. And expels the remaining waste as feces. The mouth, esophagus, stomach and intestines are part of the gastrointestinal tract. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines. A tract is a collection of related anatomic structures or a series of connected body organs. All bilaterians have a gastrointestinal tract, also called a gut or an alimentary kindail. This is a tube that transfers food to the organs of digestion. In large bilaterians, the gastrointestinal tract generally also has an exit, the anus, by which the animal disposes of feces solid wastes. Some small bilaterians have no anus and dispose of solid wastes by other means, for example, through the mouth. The human gastrointestinal tract consists of the esophagus, stomach, and intestines, and is divided into the upper and lower gastrointestinal tracts. The GI tract includes all structures between the mouth and the anus, forming a continuous passageway that includes the main organs of digestion, namely, the stomach, small intestine, and large intestine. However, the complete human digestive system is made up of the gastrointestinal tract plus the accessory organs of digestion the tongue, salivary glands, pancreas, liver and gall bladder. The tract may also be divided into four gut, mid-gut, and hind-gut, reflecting the embryological origin of each segment. The whole human GI tract is about 9 meter 30 feet long at or top seat. It is considerably shorter in the living body because the intestines, which are tubes of smooth muscle tissue, maintain constant muscle tone in a halfway tense state but can relax in spots to allow for local distention and peristalsis. The gastrointestinal tract contains trillions of microbes, with some for thousand different strains of bacteria having diverse roles in maintenance of immune health and metabolism. Cells of the GI tract release hormones to help regulate the digestive process. These digestive hormones, including gastrin, secretin, cholecystoconin, and ghrelid, are mediated through either intracurin or autocrine mechanisms, indicating that the cells releasing these hormones are conserved structures throughout evolution.