The ontogenesis of cranial neuromeres in the rat embryo. I. A scanning electron microscope and kinetic study.

摘要: The development of the cranial neuromeres, rostral to level first somite, in rat embryos during neurulation is described. Examination scanning electron micrographs 4-, 8-, 12- and 16-somite-stage has shown that neuromeres develop a strictly ordered pattern but sequence not either rostrocaudal or caudorostral direction. two mesomeres are by subdivision previously formed mesomere, whilst rhombomeres independently each other. At completion nine (including preotic sulcus) no prosomeres identifiable. A direct correlation position peaks mitotic index along embryonic axis with sulci on surface neural epithelium, was possible. However, it suggested peak initial means identifying neuromere, once neuromere expressed morphologically as sulcus returns its basal level.