Picture of Stomach
The stomach is the muscular organ that receives food and drink after they travel down the esophagus. The separation between the esophagus and the stomach is a valve called the lower esophageal sphincter. The stomach lining contains muscular folds called rugae. The stomach releases enzymes and acid to help digest food. The stomach contracts and churns, turning stomach contents into a partially digested substance called chyme. Chyme passes from the stomach through the pyloric sphincter into the small intestine where it is further digested. The stomach is situated in the upper left part of the abdomen.
Text Reference: "Stomach." Structure & Function of the Body.