an enlarged cross-sectional view of a bronchiole reveals the tissue layers that make up the wall
Ciliated simple columnar cells from the epithelial lining in the large bronchioles. In the small
bronchioles the epithelium changes to simple cuboid cells Goblet cells and seromucous glands become less numerous with each bronchiole division
A ring of smooth muscle fibers surrounds the epithelium During exhalation these muscle fibers contract to help force air out of the bronchioles The resulting compression causes the the epithelim to fold