Menu Thumbnails


Bronchiole. Intrapulmonary bronchi undergo several generations of branching and become reduced in diameter as a result of the branchings. When they reach about 1mm in diameter, they lose their cartilage plates and become known as bronchioles. These structures are lined by respiratory epithelium and contain obvious bands of smooth muscle in their walls. The patency of bronchioles is maintained by the elasticity of the lung.