Human anatomy, including structure and development and practical considerations . the peripheral portion of the supporting framework adjoiningthe outer border of the neural wall becomes denser and free from nuclei and is converted into the marginal zone ( Randschleier ofFig. S56. His), that is continuous with the r g Urn delicate reticulum pervading the otlier parts of the wall. The in-different cells later differentiateinto (a) the spongioblasts fromwhich the characteristic constitu-ents of the definite supportingtissue, the neuroglia, are derived,and [b) the neuroblasts that aredirectly conv
Human anatomy, including structure and development and practical considerations . the peripheral portion of the supporting framework adjoiningthe outer border of the neural wall becomes denser and free from nuclei and is converted into the marginal zone ( Randschleier ofFig. S56. His), that is continuous with the r g Urn delicate reticulum pervading the otlier parts of the wall. The in-different cells later differentiateinto (a) the spongioblasts fromwhich the characteristic constitu-ents of the definite supportingtissue, the neuroglia, are derived,and [b) the neuroblasts that aredirectly converted into the neu-rones. Within the resulting cell-complex that for a time occupiesthe greater part of the wall ofthe neural tube, it is difficult todistinguish with certainty between the neuroglia and neuron-producing elements, since bothare often elongated in shape and prolonged into processes. Histogenesis of the Neuroglia.—In addition to the extension, and moulding(by the developing ner\e-cells and fibres) that the primary syncytial mesh work undergoes elm. Segment of wall of neural tube of pig embryo of 10 mm.; radialstrands (r) of syncytium and differentiation of ependymal (at. nuclear(b) and marginal (»/) layers; Urn. elm, internal and external limitingmembrane; ir. dividing cell;/. pia mater. • 690. {Hardesty.) Fig. S57.
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Keywords: ., bookauthormc, bookcentury1900, bookdecade1910, booksubjectanatomy
