Prenatal development of neurons in the brain of goat.

摘要

The prenatal development of the neurons in the brain of goats was studied using 52 fetuses ranging from 1.4 (24 days of gestation) to 41.5 cm CRL (full term). By 24 days, the middle mantle layer of the neural tube showed two types of cells, namely the larger neuroblasts and the smaller spongioblasts. Primitive neurons could be clearly distinguished from spongioblasts at 40 days. Aggregation of neuroblasts, the nuclei, first appeared in the seventh week in the thalamus, mesencephalic tegmentum, pons and medulla oblongata. Neurofibrils appeared in the cytoplasm of neurons towards the middle of gestation. The Nissl granules appeared in the middle of the fourth month. Most of the neurons of the brain differentiated during the fourth month. Nuclei of most of the neurons were vesicular, centrally placed with dark staining nucleoli. In the granular layer of cerebellum, the nuclei were chromatic and non-vesicular. Towards full term, neurons in all parts of the brain were already well developed.