The small intestine's functions are divided into three parts: the duodenum, the jejunum, and the ileum.

The Duodenum (the first 25 cm) receives bile from the liver and pancreas.
The Jejunum is responsible for absorbing nutrients into the blood stream.
The Ileum is a backup to the Jejunum, and it also absorbs vitamin B12 and bile salts.

The Small Intestine

The small intestine should not be underestimated by its name. The average small intestine of a human is about 6 meters long. It gets its name from the size of its circumference (2.5cm) in relation to the large intestine, which is where the chyme is transferred to after its process within the small intestine.