The pyloric sphincter is a muscular valve located at the lower end of the stomach, connecting it to the small intestine. Its primary function is to regulate the passage of partially digested food, known as chyme, from the stomach into the duodenum, the first part of the small intestine. This process is essential for proper digestion and nutrient absorption. When the stomach contracts, the pyloric sphincter opens to allow small amounts of chyme to enter the small intestine. It then closes to prevent backflow, ensuring that the digestive process occurs in a controlled manner. This mechanism helps maintain the efficiency of the digestive system.