Ciliary epithelium of the human trachea. Labels: a, layer of longitudinally arranged elastic fibers; b, basement membrane; c, deepest cells, circular in form; d, intermediate elongated cells; e, outermost layer of cells fully developed and bearing cilia.

Ciliary Epithelium

Ciliary epithelium of the human trachea. Labels: a, layer of longitudinally arranged elastic fibers;…