During an asthma attack the muscle wall contracts and the lining of the airways becomes swollen and inflamed. These changes cause a narrowing of the airways which is further aggravated by an increase in secretions from the mucus membrane, which may actually block the smaller airways.
Does asthma cause bronchial constriction?
This muscle contraction causes the bronchus to narrow and restrict the amount of air passing into and out of your lungs. Bronchoconstriction usually occurs in asthma, emphysema, and other lung diseases. However, bronchoconstriction can also happen to those without any lung disease during intense exercise.
What causes bronchial constriction?
The bronchial spasm is due to the activation of parasympathetic nervous system. Postganglionic parasympathetic fibers will release acetylcholine causing the constriction of the smooth muscle layer surrounding the bronchi. These smooth muscle cells have muscarinic M3 receptors on their membrane.
