[EMBRYONIC SOURCES OF "RESERVE CELLS" DEVELOPMENT IN THE EPITHELIAL LINING OF THE CERVIX]

Using general histological and immunohistochemical methods, the sources of "reserve cells" of the epithelial lining of the uterus and vagina were studied on the material obtained from human embryos and fetuses. From 13th to 20th week of fetal development, the epithelial lining of the cervix was formed with the participation of the urogenital sinus (UGS). The cells of the latter interacted with the coelomic epithelial cells of the paramesonephric ducts (PMD). After 25th week, UGS cells were dispersed along the length of the cervix, lying on the basement membrane beneath the columnar epithelial cells. It is suggested that epitheliocytes of UGS are the source of the "reserve cells". Taking into account the tissue nature of the "reserve cell" it is expedient to determine them as mesonephroblasts. Cells are present in the cervical epithelium as a concomitant determined cellular differon.