The small intestine is part of the gastrointestinal tract (gut) between the stomach and the large intestine. It has three parts: the duodenum, the jejunum and the ilium. In adults, the small bowel is about 600cm, and in children it is about 300cm. Although the small intestine is four to five times longer than the large intestine, it is called the small intestine because it has a smaller diameter, about half the diameter of the large intestine.
Food from the stomach is pushed into the duodenum by a muscle called the pylorus. The small intestine is responsible for absorbing and digesting the majority of foods and nutrients we eat. These include:
- Vitamins and Minerals
- Some Fluids and Electrolytes (chemicals needed for nerve and muscle function)
When the small intestine fails because of a lack of proper length or the inability to absorb nutrients, a patient is unable to take in adequate calories to survive. This condition requires the use of intravenous nutrition known as Total Parenteral Nutrition (TPN). Long-term use of TPN can cause serious problems, including liver dysfunction or failure. However, not all patients with intestinal failure require evaluation for transplantation. Only about 20 percent of patients on TPN have serious or life-threatening complications from the TPN and need to be considered for intestinal transplantation.