Caption: Asthma inhaler. Artwork showing the effects of an asthma inhaler containing bronchodilator drugs on the lungs of a man. Bronchodilator drugs work by widening the airways (the bronchioles) of the lungs. This effect is illustrated by the enlarged bronchiole at lower left. During an asthma attack, bronchioles become narrow following contraction of the muscle layer and swelling of the mucous lining. This leads to impaired breathing. Bronchodilator drugs act on the nerve signals that govern muscle activity in the bronchioles, thereby relaxing the muscles and restoring normal breathing.
Model release not required. Property release not required.