The anatomy of the nervous system, from the standpoint of development and function . Marginal layer Ependymal layerMesoderm Marginal layer 5 ..SfSfV--*,; ***£»*? -V. Internal limiting membrane Ependymal layer Mm V £4 ^Germinal i ce// SpHfe External limiting membraneExternal limiting membrane Mantle layer Internal limiting membrane Germinal cell Internal limiting membrane. Mesoderm Marginal layer * Mantle layer Ependymal layer Fig. 19.—Early stages in the differentiation of the neural tube: A, From a rabbit embryobefore closure of neural tube; B, from a 5 mm. pig embryo after closure of tube; C
The anatomy of the nervous system, from the standpoint of development and function . Marginal layer Ependymal layerMesoderm Marginal layer 5 ..SfSfV--*,; ***£»*? -V. Internal limiting membrane Ependymal layer Mm V £4 ^Germinal i ce// SpHfe External limiting membraneExternal limiting membrane Mantle layer Internal limiting membrane Germinal cell Internal limiting membrane. Mesoderm Marginal layer * Mantle layer Ependymal layer Fig. 19.—Early stages in the differentiation of the neural tube: A, From a rabbit embryobefore closure of neural tube; B, from a 5 mm. pig embryo after closure of tube; C, from a 7 embryo; D, from a 10 mm. pig embryo. *, Boundary between nuclear and marginal layers.(Hardesty, Prentiss-Arey.) This last statement requires some qualification. The fibers of the olfactory nervearise from cells in the olfactory mucous membrane. The fibers of the mesencephalic rootof the trigeminal nerve, which in all probability are sensory, arise from cells located withinthe mesencephalon. The optic nerve is also an exception, but this is morphologically afiber tract of the brain and not a true nerve. An ingenious theory, advanced by Schulte andTilney (1915), attempts to bring this mesencephalic root and the optic nerve into more ob- HISTOGENESIS OF THE NERVOUS SYSTEM 39 vious relation with the other sensory nerves. They assume thai the pari o
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectnervoussystem, bookye
