The small bowel is with approximately 3 m the longest organ in the digestive tract and connects the stomach to the large bowel. There are three sections: the duodenum, the jejunum and the ileum.
The duodenum is about 24 cm long and begins at the pylorus of the stomach. Bile and pancreas enzymes are added to the bowel content at the papilla.
The actual digestion takes place in the jejunum and the ileum. The food is broken down to its components. Here fat, proteins, glucose, electrolytes, vitamins and water are being absorbed and carried away through the portal circulation.
The loss of greater parts of the small bowel can lead to general malnourishment or to malabsorption of certain substances (like Vitamin B12).