File:The anatomy of the nervous system, from the standpoint of development and function (1920) (14776719694).jpg

Identifier: anatomyofnervou00rans (find matches)
Title: The anatomy of the nervous system, from the standpoint of development and function
Year: 1920 (1920s)
Authors: Ranson, Stephen Walter, 1880-1942
Subjects: Nervous System
Publisher: Philadelphia : W. B. Saunders
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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vel of the cord (Figs.55, 60). The white matter is voluminous and contains the long fiber tractsconnecting the brain with the more caudal portions of the cord. The graymatter is also abundant, as we might expect from the large size of the seventhcervical nerve. The ventral column is especially thick and presents a prominentlateral angle. The large laterally placed nerve-cells of the anterior column areassociated with the innervation of the musculature of the arm. The posteriorcolumn is relativelv slender, but reaches nearlv to the dorsolateral sulcus. I III SPINAL < <)ki) 85 MICROSCOPIC ANATOMY Neuroglia. Occupying the Interstices among the true nervous elements ofthe centra) nervous system is a peculiar supporting tissue, the neuroglia, whichis of ectodermal origin. In the chapter on Histogenesis we Learned thai fromthe original epithelium of the neural tube there are differentiated spongioblastsand neuroblasts, as well as a special epithelial lining for the tube, the ependyma.
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Fig. 61.—Ependyma and neuroglia in the region of the central canal of a childs spinal cord:A, Ependymal cells; B and D, spider cells in the white and gray matter, respectively; C, mossycells. Golgi method. (Cajal.) The latter consists of long nucleated columnar cells which line the central canalof the spinal cord as well as the ventricles of the brain (Fig. 61). In fetal lifetheir free ends bear cilia, which project into the lumen of the tube, and fineprocesses from the outer ends extend to the periphery of the cord. In the adultthere are no cilia and the peripheral processes reach the surface only along theposterior median septum and in the anterior median fissure. 86 THE NERVOUS S VST EM The neuroglia cells are differentiated from the spongioblasts. These, whenstained by the Golgi method, appear as small cells with many processes. Somehave long slender processes, the spider cells or long rayed astrocytes; others haveshort thick varicose processes, the mossy cells or short rayed as

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