What does a hyphen look like? â is a punctuation mark used to join words and to separate syllables of a single word.
Definition of gastrointestinal tract. medical. : the part of the digestive system that consists of the stomach and intestines.
The gastrointestinal (GI) tract is formed, with a few exceptions, by four concentric layers of tissue. These are, from deep to superficial, the mucosa, submucosa, muscular (or muscularis) and the serosa layers. This is the simplified version. The fact is that there are more sublayers.