Mc. Uribe et al., CYCLIC HISTOLOGICAL-CHANGES OF THE OVIDUCTAL-CLOACAL JUNCTION IN THE VIVIPAROUS SNAKE TOLUCA-LINEATA, Journal of morphology, 237(2), 1998, pp. 91-100
The structure and seasonal changes of the oviductal-cloacal junction r
emain poorly understood in most squamates. This study was undertaken t
o describe the histology of the oviductal-cloaca junction of a female
viviparous snake Toluca lineata, during gestation, previtellogenesis,
and vitellogenesis. The oviductal-cloacal junction exhibits a wider lu
men and thicker layers of connective tissue, smooth muscle layers, and
total wall width compared to the posterior vagina. The lining is char
acterized by thick, short longitudinal mucosal folds. The luminal epit
helia differ morphologically from anterior to posterior portions of th
e oviductal-cloacal junction. The anterior portion is lined with a sim
ple columnar epithelium composed of nonciliated cells. The middle port
ion is lined with stratified epithelium that contains an apical column
ar cell layer that undergoes morphological changes coincident with the
reproductive cycle. The posterior portion is lined with a stratified
squamous epithelium. The connective tissue underlying the epithelium c
ontains numerous ovoid cells having abundant acidophilic cytoplasmic g
ranules-eosinophils. Copulation occurs during the previtellogenic stag
e, as evidenced by the presence of abundant spermatozoa in the lumen o
f the anterior portion and of a copulatory plug in the middle and post
erior portion of the oviductal-cloacal junction. J. Morphol. 237:91-10
0, 1998. (C) 1998 Wiley-Liss, Inc.