Neurofibril

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neurofibril

[¦nu̇r·ō′fī·brəl]
(neuroscience)
A fibril of a neuron, usually extending from the processes and traversing the cell body.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Neurofibril

 

a microscopic filament that is found upon treatment of nerve cells—neurons—and the longest outgrowths of the nerve cells—axons—with silver salts and other reagents.

In the late 19th and early 20th centuries, neurofibrils were ascribed the function of conducting nerve impulses. This view proved to be erroneous when it was found that nerve impulses are conducted by the external membrane of the neuron. Electron microscopy revealed two kinds of longitudinal neurofibrils in the outgrowths of neurons: neurotubules and neurofilaments. Neurotubules are from 20 to 25 nm in diameter and are formed from the protein tubulin; they are believed to transport substances along the axon. The threadlike neurofilaments are formed from a protein similar to the muscle protein actin. Neurofilaments are especially numerous in the movable terminal portions of growing axons.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.