The absorption allows passage of nutrients resulting from digestion, along with water, minerals and vitamins, which do not need digestion, from the intestine to the circulatory system, which will take them to the cells. All nutrients are absorbed in the small intestine, except for water, which is absorbed in the large intestine.
The walls of the intestine are lined by numerous folds called intestinal villi, which greatly increases the absorption surface. They have many blood capillaries that allow digested nutrients to be absorbed and passed into the bloodstream.
In addition, to further increase the surface area, the intestinal cells have numerous folds called intestinal microvilli, achieving an absorption surface of about 400 m2.