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An electron microscopic study of the newt ( Triturus viridescens ) Optic Nerve
Author(s) -
Turner James E.,
Singer Marcus
Publication year - 1974
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.901560102
Subject(s) - biology , ependyma , anatomy , ependymal cell , triturus , cytoplasm , optic nerve , ganglion , microbiology and biotechnology , neuroscience , spinal cord , central nervous system
The newt ( Triturus viridescens ) optic nerve appears to be more primitive than that of higher vertebrates. Only one type of glial cell is present and their stellate cell bodies are located in the core of the nerve. They send radiating processes to the surface to form a glial limitans beneath the meninges. The processes and their branches enwrap fascicles of naked axons and scattered myelinated fibers. The position and cytological character of these cells and their processes suggest that they are primitive ependyma. They subserve the functions of astrocytes and oligodendrocytes, in the latter case forming myelin wrappings. The position of their cell bodies is reminiscent of that of embryonic ependymal cells which surround the lumen of the optic stalk of vertebrates during eye development. Their cytoplasm is of medium to high cytoplasmic density, contains numerous cytoplasmic organelles and exhibit both microtubules and microfilaments.