Some scanning electron microscopic features of human cervical epithelium in cell culture.

Human cervical epithelial cells, growing out in confluent monolayers from small explants, develop cytoplasmic extensions from the margins of the growth, extending out and terminating on the glass substrate. The marginal fibrils are particularly frequent on the edges of cellular lamellipodia, protruding in advance of the growing edges. Marginal cells with microvilli tend to have more marginal fibrils on their leading edges than smooth more differentiated cells, and occasionally there is continuity between microvilli and marginal fibrils. Where there is cellular overlap, marginal fibrils extending over the surface of another cell can be seen; where these is an intercellular cleft, cytoplasmic bridges have the same appearance as marginal fibrils. Colchicine (10-6 M) did not affect marginal fibril formation.