How the Digestive System Works
The digestive system processes food and liquid into smaller parts that can be used by the body to build and nourish cells. The process begins when food and liquids enter the mouth and ends in the small intestine. The digestive tract includes a series of organs joined in a long, winding tube from the mouth to the anus.
The mechanical tasks for storing, mixing and emptying occur in the stomach. Muscles in the upper stomach relax and allow swallowed food and liquid to enter. The lower part of the stomach uses muscles to combine the swallowed items with digestive juices produced by the stomach. Finally, the stomach empties its content into the small intestine.
Through the small intestine the food is digested and dissolved by juices from the pancreas, and liver as well as the intestine. Lastly the contents are mixed and pushed forward for further digestion.
How Does Surgery Promote Weight Loss?
Bariatric surgery alters the digestive process. The operations can be divided into three types: restrictive, malabsorptive, and combined restrictive/malabsorptive. Restrictive operations limit food intake by creating a narrow passage from the upper part of the stomach into the larger lower part, reducing the size of the stomach to create an earlier sense of fullness. Malabsorptive operations do not limit food intake, but instead reduce the amount of intestine that comes in contact with food so that the body absorbs fewer calories. Combined operations use stomach restriction and a partial bypass of the small intestine.