4-piece bronchial model

This 4-piece bronchial model is a four-level section of the bronchi showing the evolution of tissues occurring in cases of asthma and chronic bronchitis.
Four stages: normal bronchi, hypersecretion of mucous gland, swelling with lymphoid aggregates, and smooth muscle spasms.
The model includes: cartilage, mucous glands and mucus, spiraled smooth muscles, and fibroelastic connective tissue and bronchial epithelial layers.
All stages rotate on a hinge pin.

Dimensions (L x W x H) = 9.4 x 3.81 x 4.45 cm