Gastrointestinal

The term, “Gastrointestinal” or “gut,” refers to the digestive tract. It is the part of the body where food is taken in and digested. After digestion, energy and nutrients from the  food material are extracted and the remaining wastes from it (those termed as “useless” materials) are expelled out of the body.

The primary process of the GI tract can be summarized as follows:

1) Ingestion - taking in the substance through the mouth into the gastrointestinal tract, usually through eating or drinking.

2) Digestion - the breaking down of chemicals (from the "ingested" food) in the body, into a form that can be absorbed.

3) Absorption - collection and distribution of the nutrients.

4) Defecation - the elimination of waste material (solid, semisolid or liquid) from the GI tract via the anus.

The GI tract is divided into two parts, the upper gastrointestinal tract and the lower gastrointestinal tract. The upper GI tract consists of the mouth, pharynx, esophagus, and stomach. The lower GI tract, on the other hand, comprises the intestines (small intestine- duodenum, jejunum, ileum; large intestine - cecum, colon, rectum) and the anus.

The GI tract also has "accessory organs" that aid its main functions. The accessory organs in the GI tract include the liver, gallbladder, and pancreas. The liver secretes bile into the small intestine, aiding digestion; the gall bladder serves as the "reservoir" of this bile. The pancreas secretes several enzymes which also aids digestion.