Morphogenesis and histogenesis of olfactory bulb in goat foetuses*

Abstract

Prenatal development of olfactory bulb in goat was studied using 52 goat foetuses ranging from 1.4 cm CRL (24 days of gestation) to 41.5 cm CRL (full term). The olfactory bulb was well developed histologically by 48 days of gestation, which projected cranioventrally from the frontal pole of the cerebral hemisphere. The lateral ventricle extended into the olfactory bulb. By 81 days, the olfactory peduncle was divided into medial and lateral olfactory striae separated by the olfactory trigone. During the third month, the olfactory bulb did not project beyond the frontal pole and was ovoid in shape. By the fifth month, the mean width exceeded the mean height and its lumen was greatly reduced. Histologically, by 24 days of gestation the wall showed inner ependymal, middle mantle and outer marginal layers. By 58 days, cortical migration of cells was evident and during the fourth month, the cortical tissue showed stratification into outer molecular, superficial granular, intermediate granular and deep granular layers. Towards term, the olfactory bulb was fully developed and the wall was differentiated into anterior layer of olfactory nerve fibres, the glomerular layer, the mitral cell layer, internal granular layer and the white matter.