Its purpose is to prepare food for use by cells and organs throughout the body. Because large food particles cannot reach cells, the process of digestion breaks the food down into nutrients that can be absorbed into the blood stream and carried to any cell in the body. The methods of digestion are mechanical and chemical. Each segment of the digestive system has a special design to perform a unique function that is an essential part of the digestive process.
Digestion begins in the mouth and is completed at the anus.
As food moves through the digestive tract, it passes through several compartments. Accessory organs that produce digestive enzymes drain their contents into the compartments at different points along the way. Each compartment and accessory organ serves a specific function. At each stage, the food is transformed into a slightly different form that allows it to be passed along to the next compartment. As it moves through the digestive tract, nutrients and water are extracted, producing waste.