We turn now to the anatomy of the organs in which nutrients and water are extracted for use by the body and by which the resulting waste material is excreted from the body. The small intestine is the organ in which most of the absorption of nutrients and water occurs. We review its anatomical divisions, blood supply, and microstructure. We turn next to the large intestine, or colon, which absorbs remaining water and transfers the feces to the rectum for excretion.