A healthy GI tract breaks down food into nutrients (e.g., proteins, carbohydrates, fats, vitamins, and minerals) that are needed by the body to thrive and survive. On the other hand, an unhealthy GI tract can cause discomfort, pain, disease, and even death.

MOUTH: In the mouth food is broken down by the teeth and mixed with saliva. Muscles in the tongue and mouth move the food into the esophagus.

ESOPHAGUS: This muscular tube connects the mouth with the stomach. At the end of the esophagus, just before the stomach, there’s a valve or ring. When closed, food and acid can’t flow back from the stomach into the esophagus, preventing heartburn.

STOMACH: The stomach mixes food with acids that break down food into small particles. Eventually, the stomach turns the food into a thick liquid. This liquid is slowly released into the small intestine.

SMALL INTESTINE: The small intestine is where most of our nutrients get absorbed. It is more than 6 metres (about 18 ft ) long. By the time food goes through the small intestine and enters the large intestine, nearly all the nutrients have been absorbed into our body. Our bodies can’t digest food without a pancreas, liver, or gall bladder.

PANCREAS: The pancreas makes strong digestive juices that are released into the small intestine. These juices break down fats, carbohydrates, and proteins. The pancreas also makes insulin that helps balance our blood sugar.

LIVER: The liver does many important jobs. For example, it makes a liquid called bile which breaks down fat. The liver also breaks down liquid from the small intestine into nutrients that are absorbed into the blood (e.g., glucose). Glucose is needed to fuel our brain and muscles.

GALL BLADDER: The gall bladder stores bile (from the liver) until it’s released into the small intestine. In addition to breaking down fat, bile breaks down stomach acids that are mixed with food.

LARGE INTESTINE: The large intestine removes water from what is left of the original food we ate. The waste that is left is known as feces (stool). The stool is stored in the rectum until it’s released (known as a bowel movement) through the anus.

Key References:

American College of Gastroenterology. (nd). Understanding your GI tract. Digestive health and disease: A glossary. Retrieved November 23, 2009, from http://www.gi.org/patients/gitract/index.asp

Gastroenterological Society of Australia. (2006). The digestive system. Retrieved December 4, 2009, from gesa.org.au/index.cfm