The function of the stomach is to store and partially digest food. The stomach is a J-shaped sack that lies between the esophagus and the small intestine.
The top of the stomach is called the fundus. The central part of the stomach is the cardiac portion, while the lower part is called the pyloric portion. At the end of this portion is the pyloric sphincter, which opens to allow entry into the duodenum, which is the upper part of the small intestine.
The stomach is muscular, which allows it to churn food. It secretes mucus to lubricate the food and hydrochloric acid and enzymes to help break it down.