Upper and Lower human gastrointestinal tract
The human gastrointestinal tract (GI tract), digestive tract, guts or gut is the system of organs within humans that takes in food, digests it to extract energy and nutrients, and expels the remaining matter. The major functions of the gastrointestinal tract are ingestion, digestion, absorption, and defecation.
In an adult male human, the GI tract is approximately 6.5 metres (20 ft) long and consists of the upper and lower GI tracts. The tract may also be divided into foregut, midgut, and hindgut, reflecting the embryological origin of each segment of the tract.
The upper Gastrointestinal tract consists of the mouth, pharynx, esophagus, stomach, and duodenum proximal to the ligament of Treitz (or the Suspensory muscle of the duodenum).
- The mouth (or buccal cavity) contains the openings of the salivary glands; the tongue; and the teeth.
- Behind the mouth lies the pharynx which prevents food from entering the voice box and leads to a hollow muscular tube, the esophagus.
- Peristalsis takes place, which is the contraction of muscles to propel the food down the esophagus which extends through the chest and pierces the diaphragm to reach the stomach.
- Small intestine, two of the three parts:
- Large intestine, which has three parts:
- Cecum (the vermiform appendix is attached to the cecum).
- Colon (ascending colon, transverse colon, descending colon and sigmoid flexure)
