The main function of the digestive system is to convert food to energy and eliminate waste. The human digestive system is made up of several parts, including the mouth, esophagus, stomach, small and large intestines, pancreas, liver, gallbladder, rectum and anus.
Each organ in the digestive system performs a specific function vital to the digestive process. While it is possible for a person to live without the gallbladder, in general, these organs are considered necessary for the human body to function properly. Digestion begins in the mouth as saliva breaks down the food and the teeth prepare the food to enter the esophagus.