Pathophysiology of Asthma: Fill in the Blank

A nurse is reviewing the pathophysiology of asthma with a group of nursing students. One of the key features of asthma is the presence of chronic inflammation in the airways, leading to episodes of wheezing, shortness of breath, and coughing. In asthma, the airways become narrowed due to muscle _______ in addition to the inflammation. This narrowing can significantly impede airflow, particularly during expiration.