Here is some information about the small intestine that should be very interesting to everyone:

Duodenum:
-means "12," the structure is 12 fingers breadth in length.
-starts at the Pyloric sphincter and extends about 25 cm (10 inches).
-it is divided into the superior part of which is the duodenal cap, the descending part into which the bile and pancreatic ducts open, the horizontal part and the ascending part terminating at the duodenojejunal junction.
-the highest level of absorption of food stuffs happens in the plicae circulars which begin in the duodenum and end in the midportion of the ileum.

Jejunum:
-means "empty," so named because at death it is found empty.
-starts at the conclusion of the duodenum and extends about 244 cm (8 feet).
-it is of a larger diameter than the ileum, has a thicker wall and is redder in appearance due to it being more vascular.
-contains plicae circulars for highest level of absorption.

Ileum:
-from the Greek eileo which means "twisted."
-starts at the conclusion of the jejunum and extends about 2 meters (6 feet).
-the terminal end of the small intestines and the ileum is at the ileocecal sphincter.
-mid way through the ileum the folds of the mucosa stop extending all the way around the circumference of the intestines and beginning to only extend part of the way around. The last half of the ileum does not have the enhanced absorption capabilities.