Digestion: The Basics

Before you can learn about operations used to treat obesity, you need to know a little bit about the process of digestion.

• The process of breaking food down into the substances used by the body is called digestion.
• Digestion begins in the mouth, where chewing breaks food up into small particles.
• After swallowing, the food moves through the esophagus, stomach, and intestines (bowels), also called the "digestive tract."
• As food moves through the digestive tract, it is broken down by enzymes and digestive juices.
• Once broken down in this way, individual components of the food such as proteins, carbohydrates, and other nutrients are absorbed into the wall of the small intestine. Different components of food are absorbed in different parts of the small intestine known as the duodenum, jejunum, and ileum.
• The process is aided by strong acids in the stomach and by bile and pancreatic enzymes in the duodenum.
• Undigested food particles collect in the large intestine (colon). They are eliminated from the body as feces.