Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 FIG. 38.—Nerve fibres (partly after M. Schultze). a, non-medullated sympa- thetic fibre, b, medullated fibres, one of them with commencing coagulation of the axis cylinder, c, medullated nerve fibre with the sheath of Schwann. FIG. 37.—a bipolar ganglion cell, b, nerve cell, from the human spinal cord (anterior cornu), (after Gerlach). P, pigment body. quently enclosed in a nucleated sheath. The larger and smaller nerv
Elementary text-book of zoology, tr Elementary text-book of zoology, tr. and ed. by Adam Sedgwick, with the assistance of F. G. Heathcote elementarytextbo01clau Year: 1892-1893 FIG. 38.—Nerve fibres (partly after M. Schultze). a, non-medullated sympa- thetic fibre, b, medullated fibres, one of them with commencing coagulation of the axis cylinder, c, medullated nerve fibre with the sheath of Schwann. FIG. 37.—a bipolar ganglion cell, b, nerve cell, from the human spinal cord (anterior cornu), (after Gerlach). P, pigment body. quently enclosed in a nucleated sheath. The larger and smaller nerves are composed of a number of such fibres bound together. According to the minute structure of the nervous sub- stance we distinguish two kinds of nerve fibres— (1) the so-called medullated nerves, with a double contour; (2) the non-medullated or naked axis cylinders (fig. 38, a, b, c). The former are distinguished by the fact that, on the death of the nerve and as the result of coagulation, a strongly refractile fatty substance which forms a sheath for the nerve fibre comes into view. This sheath is known as the medullary sheath, and the central fibre as the axis cylinder. The medullary sheath disappears near the ganglion cell, the axis cylinder only entering the protoplasm
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