The gastro-intestinal system is essentially a long tube running right through the body, with specialised sections that are capable of digesting material put in at the top end and extracting any useful components from it, then expelling the waste products at the bottom end. Nutrients from the GI tract are not processed on-site; they are taken to the liver to be broken down further, stored, or distributed.

by Ma.Engel Lyka M. Ilac 07/28/2012