The document summarizes the human digestive system. It begins with an overview of digestion and the role of the digestive system. It then describes how digestion begins in the mouth and travels through the esophagus into the stomach. The stomach contains acids and enzymes that break food down into a liquid called chyme. Chyme then enters the small intestine where nutrients are absorbed. Remaining waste moves to the large intestine where water is removed before waste is stored and eventually passed from the body. The document concludes by discussing common digestive diseases like diarrhea and constipation as well as their causes and prevention methods.