[Evolution of human endocervical cilio-secretory epithelium during the menstrual cycle. Scanning electron microscopy study].

The anatomy of the ventral epithelial surface of the human uterine endocervix was investigated by S.E.M. from biopsies taken at various periods of the menstrual cycle and from whole cervices obtained by hysterectomy on the 17th and 22nd day. Ciliated and secretory cells which constitute the epithelial surface appeared to be associated at random in various manners without apparent connection with the menstrual cycle. Considerable variation was observed at the same cycle period, depending on the patients. The release of mucus took place mainly according the macro-apocrine extrusion process, whose evolution was clear throughout menstrual cycle. Apocrine extrusions were found to be particularly intense and numerous from the 12th to the 16th day, with a peak on the 14th day. Some ciliated cells were also seen to exhibit protuberant mucus protrusion. The merocrine extrusion process was seen very rarely and thus seemed to be of minor importance. An evolutive provess also seems to occur at the level of ciliated cells: from the 9th to the 16th day, some secretory cells were seen to bear miniciliae of increasing length beside their typical microvillae. This could be interpreted as a transformation process of secretory into ciliated cells during the second third of the menstrual cycle.