A morphologist's approach to the vagina--age-related changes and estrogen sensitivity.

This paper reviews basic facts on vagina histology and ultrastructure with respect to passage of different substances and drugs through the epithelium. Particular interest is devoted to the action mechanism of topically-applied vaginal estrogen, its binding to receptors in different vaginal cell types, and possible local metabolic routes. Differences in estrogen sensitivity between uterus and vagina are discussed as well as the background for the high vaginal sensitivity.