Anatomy of the Stomach
The stomach is a J-shaped organ in the upper abdomen that makes up part of the digestive system. It is located between the end of the esophagus and the beginning of the first part of the small bowel (the duodenum).
The stomach is much like a bag with a lining. The lining contains these five layers:
Mucosa. The first and innermost layer, the mucosa, holds the glands that release digestive juices, called hydrochloric acid and pepsin.
Submucosa. The second layer, the submucosa, supports the mucosa. It is rich in blood vessels.
Muscularis. The third layer, the muscularis, contains muscles that help to mix food with the digestive juices.
Subserosa. This layer contains supporting tissues for the serosa.
Serosa. The serosa is the last and outermost layer. It is the lining that wraps around the stomach to confine it.
After food has been chewed and swallowed, it enters the stomach from the food pipe (esophagus). At this point, pepsin and hydrochloric acid are released and the muscles in the stomach lining create a rippling motion, which combines the food with the digestive juices. After about two to three hours, partially digested food moves into the small intestine, where it is broken down further and absorbed into the body.