Chronic bronchitis: the histologic features are chronic inflammation (usually lymphocytic) of bronchi with hyperplasia of goblet cells and mucus glands. The Reid index measures the gland to wall ratio (normally glands are 1/3 of wall thickness as measured from epithelial basement membrane to cartilage)

Reid index/normal bronchus
Chronic bronchitis
Reid index/normal bronchus
Chronic bronchitis/Goblet cell hyperplasia
Squamous metaplasia
Central cyanosis