Surface Tension (PK3)

Question 1

Why do alveoli have a tendency to collapse?

Answer 1

Surface tension creates a net force acting inwards, pulling the walls in and trying to shrink the alveolus

Question 2

What prevents alveoli collapsing due to surface tension?

Answer 2

Equal and opposite force from positive pressure in the gas phase

Question 3

Laplace’s law for spherical vessels

Answer 3

Pressure = (2 x Tension) / Radius