The digestive system involves the mouth, throat, esophagus, stomach, small intestine, large intestine, pancreas, liver and gallbladder. The main organs involved in digestion include the esophagus, stomach, and the small and large intestines.
Human digestion begins in the mouth. As soon as food enters the mouth, enzymes found in the saliva begin to process and break down the food. Next, the food is swallowed and enters the esophagus, which is a muscular tube that contracts to move food into the stomach. Once in the stomach, food is mixed and ground. The stomach also secretes acid and enzymes to break down the food even more. Next, the food enters the small intestine. The pancreas, liver and gallbladder secrete enzymes, acids and bile into the small intestine to help further break down the food. The small intestine is also the place where the nutrients are absorbed from the food. The small intestine contracts and pushes the food into the large intestine. The large intestine pulls water and salts out of the food and forms what is left into feces. The fecal matter is pushed into the rectum and is stored there until waste needs to be secreted. Once secreted, the digestion process is complete.