The apparatus used to model absorption in the small intestine can be set up like this. At regular intervals the liquid inside and outside of the Visking tubing is sampled and tested for starch ...

The structure of the small intestine is specialised for rapid absorption of small soluble food molecules.

The chyme enters the small intestine. Here, about 90% of absorption occurs. Nutrients enter the bloodstream through capillaries in villi. From there, the nutrients travel to various body cells.