Paper II
Question
Why do smokers develop emphysema.
Answer
Cigarette smoke causes chronic recruitment and activation of neutrophils and macrophages in the lung, which release excess proteolytic enzymes (particularly elastase); smoke also inhibits alpha-1 antitrypsin (the main protective anti-elastase) and generates oxidative stress that further inactivates it. This protease-antiprotease imbalance leads to progressive destruction of the elastic tissue supporting alveolar walls, causing permanent airspace enlargement — emphysema (classically centriacinar/centrilobular emphysema in smokers, affecting the upper lobes predominantly).