Stomach, organ of the digestive system. Most animals, like humans, have a single stomach, but birds and ruminants have digestive organs composed of two or more chambers. The outer surface of the stomach is smooth; the inner surface is folded into numerous complex ridges, which assist in the mixing of food with digestive juices and channel this material through the stomach into the intestines. Stomach is also filled with many acids that is necessary to digest the food that is still not in a form that can be absorbed by the cells of our body. Stomach basically processes the chewed food that is channeled down to the esophagus. It accomplishes this by making the food be grind to tinier pieces with the folds that line the inside of the stomach and produces enzymes to hasten the breakdown of food to its elementary particles. These enzymes are called gastric juices that are produced by several gastric glands that line the inside of the stomach. Gastric juices are composed mainly of weak hydrochloric acid, pepsin, water and mucin.

Weak hydrochloric acid helps dissolve some harder particles of the food not yet processed by enzymes that worked in the mouth.

Usually, the stomach digests the food in five to eight hours where the food will be eventually be channeled to the small intestine where the processed food’s nutrients is absorbed by very small projections from the lining of the small intestine.