A tightening of the smooth muscles around the airways, causing the airways to become narrower. It is then more difficult to expel air (exhale) through the narrowed airways. This is seen in asthma, as well as chronic lung disease.
A tightening of the smooth muscles around the airways, causing the airways to become narrower. It is then more difficult to expel air (exhale) through the narrowed airways. This is seen in asthma, as well as chronic lung disease.