The adjective for alveolus (singular) or alveoli (plural) is alveolar.
mammary alveolus
Around the lungs,the blood is separated from the air inside each alveolus by only two cell layers; the cells making up the wall of the alveolus and the capillary wall itself. This is a distance of less than a thousandth of a millimetre. Because the air in the alveolus has a higer concentration of oxygen than the blood entering the capillary network, oxygen diffuses from the air across the wall of the alveolus and into the blood. That is why the distance is important.
Alveolar macrophage cells work to clear particles from the alveolus by phagocytosis. If this process is overcome by continued build up of particles then the alveolus becomes damaged. Once an alveolus is blocked there isn't much you can do.
One alveolus is a singular, tiny air sac of the lung, surrounded by a network of capillaries, and through which oxygen and carbon dioxide are exchanged. A cluster of such air sacs are alveoli (plural of alveolus).
of Alveolus
Capillaries
of Alveolus
Atelectasis is the imperfect dilation of the lungs or the collapse of an alveolus.
(Alveoli are the jaw sockets for teeth, or the individual air sacs in the lungs.) "In childhood, more than one tooth can occupy an alveolus." "In each alveolus of the lung, gases are exchanged with the capillary blood."
alveolus
They can't be counted. We're talking hundreds of thousands, here. PS: Alveolus is the singular. Alveoli is the plural.