The Digestive system consist of mouth ,oesophagus ,stomuch ,pancreas and large intestine and small intestine .The working of digestive system begins of food throw mouth. Food and the mouth mix with saliva the saliva begin to the salt the food and the teeth begin to crush and grind the food. Food is fullback into the throat ,pharynx by the tongue. The pharynx is pulled upward to meet the epiglottis. Food moves down the esophagus by peristalsis. The peristaltic wave reaches the esophageal sphincter and food then enters into the stomach. The unique muscular structure of the stomach breaks the food into small pieces called "chyme". The Chyme exists through pyloric sphincter into the duodenum of the small intestine. The major portion of digestion and absorption take place small intestine. The mucosa secretes enzymes that supplement the digestive enzymes of the pancreas and liver. This completes the chemical process of digestion. The nutrients are transported by the blood to all the cells of the body. The undigested food reaches the ileo-cecal valve and enters the large intestine or colon. The colon absorbs water, manufactures vitamins, produces mucous, and form and expels feces. The large intestine pushes the feces into the rectum which stimulates the defecation reflex.