Microscopic air sacs in the lungs where gas exchange takes place between blood and the atmosphere.
Microscopic air sacs in the lungs where gas exchange takes place between blood and the atmosphere. Found at the ends of the lung's branching airways, they are lined with tiny blood vessels called capillaries. They are slightly elastic, expanding a little on inhalation. Alveoli are found only in the lungs of mammals.
Found at the ends of the lung's branching airways, they are lined with tiny blood vessels called capillaries. They are slightly elastic, expanding a little on inhalation. Alveoli are found only in the lungs of mammals.