Microscopic study of the histogenesis of ependymal cells located in the lateral ventricles of ovine fetal brain

The aim of this study is the determination of the morphogenesis of ependymal tissue cells during the fetal period to beginning of birth in lateral ventricles of sheep`s brain. The study was in the form of descriptive observation conducted on 50 sheep fetuses which were collected randomly. The length of the collected fetuses were measured and their age calculated by the formula x=2.1 (Y+17). Following fixation of the fetal brains in 10% buffered formalin they were separated from the skull and sectioned transversely caudal to the optic chiasma in order to obtain samples from the lateral ventricles. The samples were studied histologically after the histotechnique and staining procedures. Microscopically the group of neuroblastic cells surrounding the lateral ventricles consisted of ventricular and subventricular zones with intense mitotic activity in the ventricular zone. The ependymal epithelial tissue changed from pseudostratified to simple cuboidal during development. The thickness and mitotic activity of the neuroblastic mass at different parts of the lateral ventricular wall had a direct relationship with development of other parts of the brain. There was also a direct relationship between the retention of cilia in ependymal cells and the extension of the choroids plexus.