Nerve cell bodies in the spiral and vestibular ganglia of the adult rat are surrounded by thin (about ten lamellae) myelin sheaths which differ in several respects from typical axonal myelin. In some instances lamellae surrounding perikarya appear as typical major dense lines, and in others as thin Schwann cell sheets in which cytoplasm persists. Discontinuities and irregularities appear in the structure of perikaryal myelin. Lamellae may terminate anywhere within the sheaths; they may bifurcate; they may reverse their direction; or they may merge with each other. The number of lamellae varies from one part of a sheath to another. In addition, the myelin of a single perikaryal sheath may receive contributions from more than one Schwann cell, which overlap and interleave with each other. The ganglion cells are of two types: those which are densely packed with the usual cytoplasmic organelles but have few neurofilaments (granular neurons), and those which exhibit large areas containing few organelles but have a high concentration of neurofilaments (filamented neurons). The latter cell type is ensheathed by myelin which is generally more compact that that surrounding the former. The formation and the physiologic significance of perikaryal myelin are discussed.
Article| February 01 1962
THE FINE STRUCTURE OF ACOUSTIC GANGLIA IN THE RAT
From the Laboratory of Neuroanatomical Sciences, National Institute of Neurological Diseases and Blindness, National Institutes of Health, Bethesda, Maryland.
Dr. Rosenbluth's present address is Department of Anatomy, University of California School of Medicine, San Francisco
Received: July 17 1961
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright, 1962, by The Rockefeller Institute Press
Jack Rosenbluth; THE FINE STRUCTURE OF ACOUSTIC GANGLIA IN THE RAT . J Cell Biol 1 February 1962; 12 (2): 329–359. doi: https://doi.org/10.1083/jcb.12.2.329
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