It can be as little as 0.2 micrometers but the average is 0.6 micrometers.
The reason for this is that oxygen and carbon dioxide need to diffuse through this membrane very quickly to re-oxygenate the blood. The thicker the barrier, the longer the process, and since breathing is rather rapid it needs to happen fast.
Fudi
If their walls are too thick, substances like oxygen and nutrients and waste cannot pass across the cells into or out of the body.
It is just one cell thick - or 30 micrometres.
the inflamation and harding of the walls of the alveoli
Emphysema.
The walls were 5 feet thick!
The alveoli
as thick as any other renaissance buildings walls
Yes.
Alveoli in the lungs.
Alveoli