Gastrointestinal tract

Gastrointestinal tract, also referred to as GI tract, refers to the system of multi-celled animals that ingests, digests, and egests food, and in the process, extracts energy and nutrients.

In the human, the GI tract includes these components:

• mouth (buccal cavity; includes teeth and tongue
• pharynx
• esophagus
• stomach, which includes the pylorus
• small intestine, which has three parts:
  • duodenum
  • jejunum
  • ileum (not to be confused with the ilium, or hipbone, terminating in the ileocecal junction
• large intestine, or colon, which has five parts:
  • cecum
  • ascending colon
  • transverse colon
  • descending colon
  • sigmoid flexure
• rectum, terminating in the anus

In addition, the vermiform appendix is a rudimentary, evolutionarily relict organ attached to the cecum. Both the gall bladder and pancreas serve as secretory organs to the GI tract.

The GI tract can differ substantially from animal to animal. For instance, some animals have multi-chambered stomachs.

See also body, anatomy, abdominal cavity