Alveolus. False-colour scanning electron micrograph (SEM) of an alveolus (blue), one of the microscopic air sacs of the lungs. Adjacent alveoli are separated by a porous membrane (light red) known as the interalveolar septum. An intricate network of capillaries occupies this membrane and it is in this network that the exchange between carbon dioxide and oxygen takes place. The larger ridges in the alveolus denote the positions of underlying capillaries whereas the dark areas are openings, the interalveolar pores, which connect adjacent alveoli. Magnification: x980 at 6x7cm size.
Model release not required. Property release not required.