Which histological change is associated with chronic bronchitis?

Which histological change is associated with chronic bronchitis?

• A. Hypertrophy of goblet cells
• B. Fibrosis of bronchial wall
• C. Ciliary loss
• D. Metaplasia of bronchiolar epithelium

Answer: (D)

Chronic irritation from smoking or other pollutants drives remodeling of the bronchial lining, so the epithelium adapts to ongoing stress. The normal bronchial lining is pseudostratified ciliated columnar epithelium with goblet cells that help clear mucus. Under persistent irritation, this epithelium can undergo metaplasia and become stratified squamous epithelium. This squamous metaplasia is an adaptive change that makes the surface more resistant to irritants, but it compromises the normal mucociliary clearance system because the cilia and mucus-producing specialized cells are lost or reduced. In chronic bronchitis, this epithelial remodeling helps explain why the airway surface becomes less effective at clearing mucus and debris, contributing to the productive cough and infection risk characteristic of the disease.

Chronic irritation from smoking or other pollutants drives remodeling of the bronchial lining, so the epithelium adapts to ongoing stress. The normal bronchial lining is pseudostratified ciliated columnar epithelium with goblet cells that help clear mucus. Under persistent irritation, this epithelium can undergo metaplasia and become stratified squamous epithelium. This squamous metaplasia is an adaptive change that makes the surface more resistant to irritants, but it compromises the normal mucociliary clearance system because the cilia and mucus-producing specialized cells are lost or reduced. In chronic bronchitis, this epithelial remodeling helps explain why the airway surface becomes less effective at clearing mucus and debris, contributing to the productive cough and infection risk characteristic of the disease.