SURFACE ULTRASTRUCTURE OF FETAL BRONCHIAL EPITHELIUM IN CAMEL

The surface ultrastructural features of fetal camel bronchial epitheli um were studied at various stages of development. The bronchial epithe lium in fetuses of 90-280 mm crown-to-rump length (CRL) presented a la rge number of disintegrating sloughed epithelial cells and a few cilio genic cells at different stages of ciliary differentiation. The disint egrating cells had vacuolated electron lucent cytoplasm, which contain ed variable amounts of glycogen, swollen mitochondria, strands of dila ted rough endoplasmic reticulum and irregular pyknotic nuclei. They we re joined by a distorted junctional complex at their luminal ends. Fro m 330-480 mm CR length fetuses, the disintegrating sloughed cells of t he bronchial epithelium of camel lung were relatively fewer than those observed at the previous fetal stage. On the other hand, the non-cili ated microvilli-covered cells and the ciliogenic cells were increased in number. On reaching 500-560 mm CR length, the disintegrating slough ed cells had completely disappeared from the bronchial surface, and th e lining epithelium was characterized by the presence of abundant cili ogenic cells at various stages of differentiation. Towards 570-700 mm CR length, most of the bronchial surface cells underwent ciliogenesis. From 830 mm CRL up to term, the bronchial epithelium demonstrated cil iated and non-ciliated microvilli-covered cells, together with some ce lls possessing microplicae at their apical surface.