SURFACTANT (PAGE 26)
The law of laplace states Pressure = 2 (surface tension) / radius.
No surfactant: If there is no surfactant, and if we say that both the surface tension of the smaller
alveoli and the bigger alveoli are equal, but the bigger alveoli has a bigger radius then the
smaller alveoli, then we can say using the formula that the smaller alveoli has a higher pressure
than the bigger one.
(If smaller alveoli has a radius of 1, and bigger has a radius of 2, then from putting these
numbers into the formula, the smaller alveoli yields a bigger pressure.)
So since the smaller has a bigger pressure, the air will flow from the smaller alveoli (B) to the
bigger alveoli (A). What will then happen is that eventually, the smaller alveoli will just collapse
and die down into the bigger alveoli and they will become one.
- Makes gas exchan