Understanding the Digestive Tract

To understand the role bariatric surgery plays in helping severely obese patients lose significant weight, it is important to understand how the body's digestive system or tract works. 

Starting with your mouth and ending at the anus, the digestive tract is a virtual symphony of movement, mixture and nutrient absorption. Organs making up the digestive tract include the mouth, esophagus, stomach, small intestine, large intestine-also called the colon-rectum, and anus. As food travels along this path, digestive juices and smooth muscles help break down food and liquids into the molecules that are carried to the body's cells for nutrients, energy, and growth.

After food is chewed and swallowed, it first passes through the esophagus into the stomach, where it is mixed with juices before passing in small amounts into the small intestine. In the small intestine, nutrients are absorbed into the bloodstream. Absorption is the most important part of the digestive process. Within the small intestine, carbohydrates, proteins, fats, and vitamins are absorbed by microscopic villi lining the mucosa. Digested and undigested food, fiber, and waste then pass from the small intestine to the large intestine, colon and rectum.

Bariatric procedures traditionally involve bypass (malabsorptive) procedures or banding (restrictive) elements that generally reduce the amount of food intake, and reduce or slow absorption of fat and nutrients by the body.