The exit of food from the stomach into the small intestine is regulated by the pyloric sphincter, a muscular ring located at the junction between the stomach and the duodenum (first part of the small intestine). The pyloric sphincter acts as a valve, controlling the release of partially digested food, known as chyme, into the small intestine. Coordinated peristaltic contractions of the stomach wall, combined with the relaxation and contraction of the pyloric sphincter, regulate the gradual passage of chyme into the duodenum. This controlled release allows for efficient digestion and absorption of nutrients in the small intestine.