Five seconds after the food is swallowed, they enter the stomach, where it will stay for up to four hours. The stomach is a J-shaped bag that expands to store food.
In the stomach, the food is made even smaller, and is broken up to different particles. Some of this, such as sugar and water, go through the walls of the stomach and into the blood stream, to give energy to the trillions of atoms around the body.
The stomach walls contain strong muscles. They squeeze and churn the food, mixing it with gastric (stomach) juices to form a thick mush called chyme. Gastric juices pour into the stomach from glands in the stomachs lining. These juices contain enzymes and hydrochloric acid (this is so strong that it could dissolve the metal zinc). The acid kills off most of the germs that may be in the food. The stomach itself is protected from the action of enzymes and acid by a thick layer of slimy mucus, but even so, half a million cells of the stomach lining die and must be replaced every minute.