Question

Considering the natural recoil properties of alveolar tissue and the surface tension of water molecules favoring alveolar contraction and resistance to expansion, what forces act to oppose these tendencies and prevent alveoli from collapsing?

Answer 1

Molecules of water are pulled together and also pull the wall of alveoli in order to recoil and tend to become smaller. The presence of intrapleural pressure and surfactant prevent alveoli from collapsing

Surfactants are spread all over the alveoli. They lower the tension on alveolar surface and prevent alveolar collapse. The also aid in easy breathing.

The negative intrapleural pressure prevents alveoli as well as lungs from collapsing and shrinking.