A reappraisal of the ultrastructure of the human respiratory nasal mucosa.

A study of the ultrastructure of human respiratory nasal mucosa using specimens of simple mucous polyps showed features essentially identical to those described in the lower respiratory tract. Minor forms of epithelial specialization seen in the nasal lining of the other mammalian species are not demonstrable in man. Inflammatory cells, especially lymphocytes, form an integral constituent of the epithelium, and are in close apposition to the epithelial cells. A marked increase in the epithelial surface area is achieved through ridging and clefting, irregularity of the cell's surface and the presence of microvilli. Branching microvilli are admixed with more conventional structures.