Development of the Human Nervous System
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Begins: Day 15 post-conception (p/c).
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Formation of primitive streak of specialized neuroectoderm on embryo’s dorsal surface.
Hensen’s Node and Neural Plate
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Hensen’s node: Small nodule at rostral end of neural plate.
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Directs development of the anterior neural tube.
Development of the neural tube and neural crest. Fig. A shows the action of dorsalising signals from the ectoderm (e.g. bone morphogenetic proteins; BMP) and ventralising signals (e.g. sonic hedgehog, SHH) from the notochord on the developing neural plate. Fig. B shows folding of the edges of the neural plate to form the neural tube. Fig. C shows covering by the mesoderm and ectoderm over the closed neural tube, and separation of the neural crest tissues. The neural tube divided by the sulcus limitans into the dorsal alar and roof plates, and the ventral basal and floor plates. (Adapted from Ten Donkelaar, et al. Clinical Neuroembryology, 2nd edition, Springer 2014.)Login to Read More
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