ABSTRACT
The adrenal medulla occupies the central area of the adrenal glands and comprises approximately 10% of the volume of the gland. Although the general structure is similar in all species, there are variations. In the mouse, rat and hamster the glands are round, while in guinea pig, dog and man they are flat. In the primate species, the marmoset, they are a flat triangular shape, while in the Rhesus monkey the glands are elongated and flat.
