Ultrastructural changes in the vaginal epithelium of the rhesus monkey during the menstrual
cycle and pregnancy were studied by scanning and transmission electron microscopy.
During the menstrual cycle, the epithelium was keratinized but varied in thickness. Cells of
the basal and parabasal layers were polyhedral in shape but as they differentiated they
accumulated glycogen and filaments. Cells in the intermediate layers had keratohyaline and
membrane-coating granules. Cells in the superficial layers had a thickened cell envelope …