The duodenum is the short first portion of the small bowel. The jejunum is the second part with the entire small bowel being over 20 feet long. The role of the jejunum is to absorb nutrients that come down from above. You notice that the lining of the jejunum shows tiny pinpoint reflections of light. This fine feathery pattern is because of the ultra tiny fronds that extend out from the lining. It is these tube-like fronds, called villi, through which nutrients move into the blood stream.