Development of the saccus and ductus endolymphaticus of the domestic fowl (Gallus gallus f. domestica)
Klika, E.; Zajícová, A.
Folia Morphologica 36(2): 214-220
1988
ISSN/ISBN: 0015-5640 PMID: 3410391 Document Number: 321892
The embryonic saccus endolymphaticus (SE) of the domestic fowl (Gallus gallus f. domestica) originates as an evagination of the otocyst from the 5th to the 7th day of embryogenesis. On the 8th day of incubation, intracranial localization of its anlage and incipient cytodifferentiation of the epithelium can be demonstrated. Cytodifferentiation is accompanied by development of a richly intricate basal labyrinth of SE epithelium, together with a marked lamina basalis. Large numbers of microvilli are formed progressively on the apical surface. The arachnoidea is formed on the 15th days of embryogenesis and develops in the mesenchyme of the differentiating subarachnoid space. From the 17th to the 21st day of development, dark and light cells are differentiated in the SE epithelium. By the 19th day the epithelium is fully differentiated, with an intricate basal labyrinth, a system of microvilli on the surface and pinocytotic and endocytotic vesicles. The mitochondrial apparatus is pronounced among the organelles. The cytoplasm of many cells is full of vacuoles with finely granular contents. The basal labyrinth.sbd.a complex of epithelial cell processes.sbd.is anchored in the ground substance of fine collagen fibrils. Mesenchymal epithelium of the subarachnoid space is wrapped round the wall of the SE, the whole of which is situated in a duplicature of the arachnoidea. The authors conclude from the structure of the SE that its epithelium possesses secretory and transport function.