The small intestine is between the stomach and the large intestine. In humans over 5 years old, a small intestine may be five to six meters long. It is where most of the digestion and absorption happens.
- The duodenum receives bile and juice from the pancreas. It is where most digestion takes place. Secretions neutralise the stomach acidity, and enzymes digest the food.
- The jejenum: the products of digestion (sugars, amino acids, and fatty acids) are absorbed into the bloodstream here.
- The ileum: absorbs vitamin B12 and bile salts and any products of digestion which were not absorbed by the jejunum.