The document summarizes the key parts and functions of the human digestive system. It describes the 30 foot long gastrointestinal tract starting from the mouth and ending in the anus. It details the main sections including the oral cavity, esophagus, stomach, small and large intestines. The three main functions are digesting foods, absorbing nutrients, and eliminating waste. Accessory organs that help digestion include the liver, gallbladder and pancreas.