Respiratory epithelium. Transmission electron micrograph (TEM) of a section through the respiratory epithelium of the lung, showing microvilli (large, hair-like), cilia (small, hair-like) and the basal bodies that are the anchoring sites for the cilia. The basement membrane (bottom) can also be seen. The respiratory epithelium is the lining of the respiratory tract, which moistens and protects the airways. Mucous and cilia act to trap potential pathogens and foreign particles, preventing infection.