Two opposing mechanisms determine alveolar expansion: ________ leads to alveolar expansion, while ________ opposes alveolar expansion.

A) lung recoil; positive pleural pressure
B) positive pleural pressure; lung recoil
C) lung recoil; negative pleural pressure
D) negative pleural pressure; lung recoil

Alveolar Expansion

The process of air sacs in the lungs enlarging during inhalation, facilitating gas exchange between the lungs and blood.

Lung Recoil

The tendency of the lungs to return to their original size after being stretched or expanded, a critical factor in normal breathing and expelling air from the lungs.

Pleural Pressure

This refers to the pressure within the pleural cavity, which is crucial in the mechanics of breathing.