Human intestines. Computer illustration showing the location of the intestines in the human abdomen (left), with insets showing the small intestine (thin, coiled) surrounded by the large intestine (thick), and a microscopic view of the lining of the small intestine (right). The interior surface of the small intestine is made up of tiny finger-like projections known as villi, each of which contains a lymph vessel and a network of blood capillaries (red and blue). The villi greatly increase the surface area across which digested food can be absorbed.