Illustration of the stomach. The stomach is approximately 6-8 inches long by 3-4 inches wide, but can expand to accommodate whatever food is eaten. In the stomach, the food is mixed with acid, mucus and pepsin, and released into the duodenum, or small intestine, at a controlled, steady rate. Hydrochloric acid and a variety of digestive enzymes are secreted in the stomach and break down the food into smaller pieces. These stomach acids kill germs in food. The lower portion of the stomach, called the antrum, has a grinding function which helps mechanically break down the food into smaller pieces.