Brown fat tissue is made up of multilocular adipocytes, which contain many lipid drops in the cytoplasm (white fat adipocytes have just one lipid drop). The nucleus is rounded in shape and the cytoplasm is pink when stained with eosin. Brown fat tissue is highly irrigated by blood vessels, that together with the large amount of mitochondria in the cytoplasm of adipocytes, make this tissue to be brownish in color. That it is why the name brown adipose tissue. Adipocytes are arrange in lobes separated by connective tissue. The function of brown adipose tissue is not to store energy for metobolism, but fat is consumed to generate heat. In most mammals, brown tissue is abundant during the perinatal period, and progressively dissapears during development. In adults is reduced to a few places of the body.