Stomach anatomy. Historical artwork of the stomach and the surrounding areas of the digestive system. Food enters the stomach from the oesophagus (upper right). The stomach is a hollow sac where the food is partially broken down by enzymes and acid that are secreted by the stomach lining, combined with the churning contractions of muscles that line the stomach wall. Partly digested food is passed into the duodenum (lower left), the first region of the small intestine. Here, further digestive fluid and enzymes are added from the liver and pancreas via the common bile duct (tube on right-hand side of the duodenum). The duodenum is where nutrients from the digested food start to be absorbed by the body.