The mucous lining of major bronchi in the rabbit lung.

Mucous secretions covering the surface of the trachea and major bronchi of the rabbit lung have been demonstrated with the scanning electron microscope. The surface secretion forms a continuous layer overlying the major airways and shows a complex 3-dimensional arrangement of overlapping sheets and fibrous networks. In the main and lobar bronchi, mucus forms more expanded networks, and in the trachea, mucus forms a smoother, more cohesive layer overlying the epithelial cells. The mucous blanket follows closely the contours of the airway epithelium and is situated at the tips of the cilia.