The lungs interface with the environment, bringing in atmospheric air during inspiration, and expelling mixed airway and alveolar air during expiration. Gas exchange occurs in the alveoli and depends on lung mechanics as well as blood flow in taking up oxygen and releasing carbon dioxide. The lungs receive all of the blood flow of the right heart, a low-pressure system that perfuses the millions of alveolar capillaries for gas exchange.

How does smoking-induced damage to lung tissue lead to emphysema?

What is the rationale for using β-agonist drugs in diseases of increased airway resistance?