the air sac itself.
An alveolus is a single air-sac, and alveoli are multiple air-sacs.
It is easy for air to pass across the wall of an air sac because the wall is thin.
The biological term for an air sac is "pneumatic sac," which refers to a structure in the respiratory system of certain animals that aids in breathing by storing or regulating air flow. These structures are commonly found in birds and some reptiles.
Alveoli is an air passage
A air sac
Air sac
Air sac
There is no specific name for this physiological feature of the kakapo. It is simply called an inflatable thoracic air sac.
there are millions of air sacs in your lungs
It's an Air Sac.
alveoli