Molecular Classification
Smooth Muscle, Contractile Tissue
Other Names
Airway Smooth Muscle, ASM
Disease Roles
AsthmaChronic Obstructive Pulmonary Disease (COPD)Bronchial Hyperreactivity

Bronchial Smooth Muscle Overview

Bronchial smooth muscle (BSM), also referred to as airway smooth muscle (ASM), is a specialized type of smooth muscle found in the walls of the bronchi and bronchioles within the respiratory tract. Its primary function is to regulate airway caliber by contracting or relaxing, thereby controlling airflow resistance and distribution throughout the lungs. BSM is implicated in diseases such as asthma and COPD, where it contributes to bronchoconstriction, inflammation, and airway remodeling. It is a therapeutic target for bronchodilators and anti-inflammatory medications.

Mechanism of Action

Modulation of airway diameter via contraction or relaxation; inhibition of inflammation and remodeling.

Biological Functions

Airway tone regulation
Ventilation distribution
Mucus clearance
Secretion of cytokines and chemokines
Immunomodulation

Disease Associations

Asthma
Chronic Obstructive Pulmonary Disease (COPD)
Bronchial Hyperreactivity

Safety Considerations

  • Over-reliance on bronchodilators may mask underlying inflammation
  • Potential for side effects from bronchodilators and corticosteroids
  • Therapeutic resistance due to remodeling of airway smooth muscle

Interacting Drugs

β2-Adrenergic Agonists
Muscarinic Antagonists
Corticosteroids