Absorption is the movement of digested food molecules through the wall of the intestine into the blood or lymph.
The small intestine is the region where digested food is absorbed. Most absorption happens in the ileum. This is the longest part of the small intestine and is between 2-4 metres long. The small intestine has a large internal surface area for absorption to happen quickly and efficiently.
The villi (one is called a villus) are tiny, finger-shaped structures that increase the surface area. They have several important features:
The hepatic portal vein transports absorbed food from the small intestine to the liver.