The persistent cough of chronic bronchitis in a smoker develops because
- A. the alveoli fill with blood
- B. the ribs lose their cartilage
- C. smoke paralyses the cilia and stimulates extra mucus, which then collects in the airways
- D. the vocal cords are permanently inflamed
Explanation
Cilia that normally sweep the mucus escalator upwards are stopped by the smoke, while the irritation makes goblet cells secrete more mucus, so it pools in the bronchi and can only be cleared by coughing. The stagnant mucus also becomes a breeding ground for bacteria, which is why chest infections are frequent. Much of this damage is reversible when a person stops smoking.