File:The anatomy of the nervous system, from the standpoint of development and function (1920) (14592900379).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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Fig. 207.—Diagram showing the direction of conduction in the olfactory nerve bulb and tract:A, lateral olfactory stria; B, anterior portion of the anterior commissure; C, bipolar cells of theolfactory mucous membrane. (Cajal.) nerve-fibers passing to and from the olfactory tract. Superficial to this are severallayers of gray matter of very characteristic structure, and this, in turn, is coveredwith the superficial layer of unmyelinated fibers from the olfactory nerve fila-ments. Within the gray matter of the bulb are found three types of neurons,the mitral, tufted, and granule cells. The large mitral cells are the most char- 276 THE NERVOUS SYSTEM acteristic element; and their perikarya are closely grouped together, forminga well-defined layer (Fig. 208, C). The tufted cells are smaller and more super-ficially placed (Fig. 208, B). The larger dendrites from both these types ofneurons are directed toward the superficial fiber layer. Each of these dendrites
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Fig. 208.—Section of the olfactory bulb of a kitten. Golgi method. A, Layer of glomeruli;B, external plexiform layer; C, layer of mitral cells; D, internal plexiform layer; E, layer of granulesand white substance; /, J, granule cells; a, b, glomeruli, showing the terminations of the olfactorynerve-fibers; c, glomerulus, showing the terminal arborization of a dendite of a mitral cell; d,tufted cells; e, mitral cell; h, recurrent collateral from an axon of a mitral cell. (Cajal.) breaks up into many branches, which form a compact rounded bushy terminal.The terminal ramifications of olfactory nerve-fibers interlace with these dendriticbranches, and the two together form a circumscribed, more or less spheric ol-factory glomerulus (Fig. 208, A). These relations were demonstrated by Cajal THK RHINENCEPHALON 277 in 1800, and possess considerable theoretic and historic interest. Since in theseglomeruli the olfactory nerve-fibers come into contact with only the dendriticramifications of the

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