Postnatal development of the cervical epithelium in the Mongolian gerbil

Abstract

This study analyzes the postnatal development of the Mongolian gerbil's cervical epithelium, in relation to its future functions. In the newborn gerbil the outline of the cervical canal is smooth, showing hardly any signs of folding. The epithelium consists of 1 to 3 layers. The cervical cells have rounded apices of regular outline and contain a large amount of glycogen. The first secretory products of specific mucus type appear about day 23 postnatally (p.n.). Initially two types of vesicles can be identified, as compared with only one type in sexually mature animals. The process of mucification begins in the vagina and the external os of the cervix and spreads towards the cervical horns. The cervical canal, besides growing longer, becomes increasingly folded during development. At about day 50 p.n., with the onset of sexual maturity, an upper endocervix and a lower ectocervix can be distinguished within the cervical canal. In the fully mature animal, the endocervix consists of 4 to 5 layers, in which apical cells mucify and exfoliate. In the ectocervix, the epithelium can be divided into 4 to 5 basal layers and 5 to 7 upper layers which mucify, keratinize, and exfoliate, according to the cyclic phases of the vagina. Diapedesis of leucocytes through the epithelium starts around day 45 p.n.

The evolution of genital shape variation in female cetaceans*

“…The cervices of T. truncatus and P. phocoena also widen as females become sexually mature, consistent with reports of ontogenetic changes in tissue composition related to the functional role of the cervix in reproduction in various mammalian taxa (El‐Banna and Haffez ; Kress and Mardi ). To our knowledge, this is the first study to show an ontogenetic change in the shape of the cervix.…”

Ultrastructural Changes in the Cervical Epithelium during the Estrous Cycle of the Marsupial <i>Monodelphis domestica</i> (Grey Short-Tailed Opossum)

“…Ultrastructural studies of the cervix exist for human females [Laguens et al, 1967;Hackemann et al, 1968;Jordan, 1976;Ludwig and Metzger, 1976;Gould et al, 1979;Kenemans et al, 1982], rabbit [Odor, 1974;Riches et al, 1975;Shingleton and Lawrence, 1976;Odor and Blandau, 1988;Odor et al, 1989;Odor, 1991], mouse [Abro and Kvinnsland, 1972], and Mongolian gerbil [Kress and Mardi, 1992] but for marsupials there exists to our knowledge no light-(LM) or electron-microscopic (EM) description of the cervical epithelium during the estrous cycle. Most authors who describe the marsupial female genital tract mention the presence of a cervix or uterine neck only very superficially and do not describe it as a special entity [Hill and Fraser, 1925;Nelson and Maxwell, 1942;Pearson, 1945;Risman, 1947;deBavay, 1951;Waring et al, 1955;Crawford et al, 1999].…”

“…Differences can be noted in the anatomy of the orifices, the complexity of cervical foldings, the epithelial transition from uterus to cervix and the possible division of the cervical canal into an endo-, ecto-or exocervix [Jurow, 1943;El-Banna and Hafez, 1972;Hafez and Jasczak, 1972;Mossman, 1987;Mullins and Saacke, 1989;Kress and Mardi, 1992]. An endocervix is lined with a columnar to pseudostratified epithelium which comprises two cell types, secretory and ciliated cells.…”

“…An ectocervix is lined with a stratified squamous epithelium similar to the lining of the vagina. The junction between endo-and ectocervix is known as the squamocolumnar junction and is very sharp [Hafez and Jaszcak, 1972;Kress and Mardi, 1992;Moghissi, 1999].…”