A client with asthma asks the nurse about the role of bronchial smooth muscle in asthma. How should the nurse explain it?
A.
“Bronchial smooth muscle has no involvement in asthma.”
B.
“Bronchial smooth muscle contracts and narrows the airways in asthma.”
C.
“Bronchial smooth muscle helps to clear mucus from the airways in asthma.”
D.
“Bronchial smooth muscle releases antibodies to protect against asthma attacks.”
The Correct Answer and Explanation is:
The correct answer is B: “Bronchial smooth muscle contracts and narrows the airways in asthma.”
Explanation:
Asthma is a chronic inflammatory disease of the airways characterized by bronchoconstriction, airway inflammation, and increased mucus production. One of the central mechanisms in asthma is the role of bronchial smooth muscle, which surrounds the airways. This muscle plays a critical role in regulating the diameter of the bronchi and bronchioles.
In individuals with asthma, certain triggers, such as allergens, irritants, cold air, or exercise, can cause the bronchial smooth muscle to contract abnormally. This contraction, known as bronchoconstriction, narrows the airways and leads to difficulty in breathing. When the bronchial smooth muscle contracts, it reduces the lumen of the airways, making it harder for air to move in and out of the lungs. This causes classic asthma symptoms like wheezing, shortness of breath, chest tightness, and coughing.
The narrowing of the airways is further compounded by inflammation of the bronchial walls and increased mucus production, which obstructs airflow. The hypersensitivity of bronchial smooth muscle in asthma results in exaggerated contractions in response to various stimuli that would not affect individuals without asthma.
Asthma management often includes medications such as bronchodilators (e.g., albuterol), which work by relaxing the bronchial smooth muscle, reducing airway constriction, and making breathing easier. Inhaled corticosteroids and other anti-inflammatory agents help reduce the inflammation that contributes to the hypersensitivity of the bronchial smooth muscle.
Thus, the bronchial smooth muscle plays a key role in the pathophysiology of asthma by contracting and narrowing the airways, leading to the characteristic respiratory difficulties seen in asthmatic individuals. Effective treatment focuses on both relaxing these muscles and reducing airway inflammation.