How does airway narrowing occurs during Asthma attack?

Question

How does airway narrowing occurs during Asthma attack?

Answer 1

Two things:

1.  Smooth muscle surrounding the bronchioles (small airways leading to the alveolae (where gas exchange actually occurs) contract, restricting airflow.  

2.  Inflammation of the airways mucosa causes swelling and narrowing of airways.

In an acute asthma attack.  Smooth muscle contraction occurs first, with airway inflammation/obstruction occurring 2-3 hours later.