Final answer:
Centriacinar emphysema affects the central parts of the alveoli and can lead to significant lung damage due to a deficiency in α1 antitrypsin, which normally inhibits destructive elastase activity.
Step-by-step explanation:
Centriacinar emphysema predominantly affects the central parts of the alveoli, particularly in the upper lobes of the lungs. This form of emphysema is characterized by the destruction of the alveolar walls, leading to a reduction in the pulmonary surface area available for gas exchange and a decrease in lung elasticity. The most significant inhibitor of neutrophil elastase, which can destroy the elastin in alveolar walls, is α1 antitrypsin. A deficiency in this enzyme leads to unchecked elastase activity, resulting in the progressive condition known as emphysema.