The stomach is a muscular organ located between the esophagus and the small intestine. It plays a crucial role in digestion by breaking down food using gastric juices, which contain acids and enzymes. The stomach's walls contract to mix food with these digestive fluids, turning it into a semi-liquid substance called chyme. After the food is processed in the stomach, it gradually moves into the small intestine for further digestion and nutrient absorption. The stomach also helps regulate the passage of food, ensuring that it is adequately broken down before entering the next stage of the digestive system.