Digestive tract
The digestive tract is a conduit connecting the mouth and the anus, consisting of many structures that deal with food. Digestive glands can secrete digestive juice to digest food. A normal male adult digestive tract is about 6.5 meters long and consists of upper digestive tract and lower digestive tract. Human upper digestive tract consists of oral, pharynx, esophagus and stomach. The mouth contains buccal mucosa, salivary glands, tongue and teeth. Behind the mouth is the pharynx, pharynx connected by the composition of the hollow tube, the esophagus. Esophagus through the muscle contraction and relaxation, the food down to push through the diaphragm to reach the stomach. Lower digestive tract includes intestines and anus. The intestine is the digestive system, from the stomach to the anus between the digestive tract, for most of the chemical digestion process of the location, the food nutrition absorption. Small intestine with annular pleats and villi. Can increase the intestinal surface area, jejunum can absorb sugar, amino acids and fatty acids and other nutrients. Ileal intestinal villi can absorb vitamin B12 and bile acids, can also absorb other nutrients. Large intestine with cecum, connected to the appendix. ...