Ultrastructure of the middle ear mucosa.

Light- and electron microscopic studies of recent years have definitely concluded that the epithelium of the middle ear is a modified respiratory epithelium with ciliated and secretory cells including goblet cells. Goblet cells are secretory cells completely filled with secretory granules. Secretory cells and ciliated cells are both derived from the basal cell. The subepithelial layer which consists of loose connective tissue is a structure of just as great importance as the epithelial layer. It is still not clear whether the dark granulated cell is the site of production of the serous middle ear effusion or whether it merely represents an immature stage of the mucigen-producing cell.