4-stage cross-section of the bronchus demonstrating the lung tissue changes occurring in asthma and chronic bronchitis. 4-stages: normal bronchus, hypersecretion of the mucous gland, swelling with lymphoid aggregations and smooth-muscle spasm. The model includes; cartilage, mucous glands and plug, spiraling smooth muscles, and the fibroelastic connective tissue and epithelial layers of the bronchus. All stages rotateon hinge pin. Model Size: (4) 1-1/2" dia. x 7/8" x 3-3/4" Card Size: 6-1/2" x 5-1/4"