So, let's wrap up this video series.
The alveoli are the only place in the lungs where oxygen and carbon dioxide are exchanged.
The walls of the alveoli and the capillaries are one-cell thick,
and that's to allow for diffusion of oxygen into the capillaries and carbon dioxide into the alveoli to be exhaled.
Now, there's three types of cells in the alveoli, Type I, Type II, and macrophages.
Surfactant is produced by the Type II cells and reduces surface tension
which helps prevent the alveoli from collapsing.
Now, the walls of the alveoli are destroyed in respiratory diagnoses like emphysema.
They're penetrated with inflammatory substances and filled with fluid in ARDS,
and they collapse due to lack of surfactant in premature infants.
Thanks for watching our video today.