The stomach is a major digestive organ. In the digestive system the stomach is involved in the second phase of digestion after mastication (chewing). The stomach is located between the oesophagus and the small intestine.It secretes digestive enzymes and gastric acid to aid in food digestion. The pyloric sphincter controls the passage of partially digested food (chyme) from the stomach into the duodenum where peristalsis takes over to move this through the rest of the intestines.