Department of Veterinary Anatomy and Histology, College of Veterinary and Animal Sciences, Mannuthy-680 651, India.
*Part of the Ph. D thesis submitted by the first author.
Histogenesis of diencephalon was studied using 46 goat foetuses ranging from 2.5 cm CRL (40 days of gestation) to 41.5 cm CRL (full term). By 40 days, the roof plate was converted into the tela choroidea and along with the growing blood vessels, formed the choroid plexus of the third ventricle. Proliferation of neuroblasts in localized regions of the mantle layer led to formation of nuclei in the seventh week. The nerve tracts also appeared at this stage. At 81 days the internal medullary lamina extended into the thalamus from the stratum zonale dividing it into medial and lateral portions. Supraoptic nucleus started developing towards the end of second month. Typical neurons appeared in most of the thalamic and hypothalamic nuclei during fourth month. During fifth month, supraoptic and paraventricular nuclei of hypothalamus showed bipolar cells. Histologically the diencephalon was adult-like towards term.
Diencephalon, Prenatal histogenesis, Goat
