Surface ultrastructure of fetal bronchial epithelium in camel.

The surface ultrastructural features of fetal camel bronchial epithelium were studied at various stages of development. The bronchial epithelium in fetuses of 90-280 mm crown-to-rump length (CRL) presented a large number of disintegrating sloughed epithelial cells and a few ciliogenic cells at different stages of ciliary differentiation. The disintegrating cells had vacuolated electron lucent cytoplasm, which contained variable amounts of glycogen, swollen mitochondria, strands of dilated rough endoplasmic reticulum and irregular pyknotic nuclei. They were joined by a distorted junctional complex at their luminal ends. From 330-480 mm CR length fetuses, the disintegrating sloughed cells of the bronchial epithelium of camel lung were relatively fewer than those observed at the previous fetal stage. On the other hand, the non-ciliated microvilli-covered cells and the ciliogenic cells were increased in number. On reaching 500-560 mm CR length, the disintegrating sloughed cells had completely disappeared from the bronchial surface, and the lining epithelium was characterized by the presence of abundant ciliogenic 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 ciliated and non-ciliated microvilli-covered cells, together with some cells possessing microplicae at their apical surface.