This model shows a four stage cross-section of the bronchus demonstrating the tissue changes occurring in asthma and chronic bronchitis. The four stages are normal bronchus, hypersecretion of the mucous gland, swelling with lymphoid aggregations and smooth muscle spasm. Cartilage, mucous glands and plug, spiraling smooth muscles, the fibroelastic connective tissue and epithelial layers of the bronchus are shown. The four stages rotate on a hinge pin for easy viewing and comparison. Supplied with key card.