role of epithelial tissue in the digestive system
Intestinal epithelium The intestinal epithelium is the layer of cells that forms the luminal surface or lining of both the small and large intestine (colon) of the gastrointestinal tract. It is composed of simple columnar epithelium. It has two important functions: absorbing helpful substances and providing a barrier against harmful substances. Some diseases and conditions are caused by dysfunction in the intestinal epithelium, and some diseases and conditions cause problems with these cells, which then leads to further complications.
Gastrointestinal tract The gastrointestinal tract (digestive tract, digestional tract, GI tract, GIT, gut, or alimentary canal) 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.