The plural of alveolus. The alveoli tend to be tiny atmosphere sacs in the lung area where in fact the trade of air and carbon dioxide occurs.
air sacs when you look at the lung area where gaseous exchange occurs. (sport: scuba)
(pl. ) of Alveolus
BUtschli, on the other hand, interprets it as a finely vacuolated foam-structure or emulsion, comparable to that which is observed when small drops of a mixture of finely powdered potash and oil are placed in water, the vacuoles or alveoli being spaces filled with liquid, the more solid portion representing the mesh-work in which the microsomes are placed.