翻訳と辞書 Words near each other ・ Nerve agent ・ Nerve allograft ・ Nerve and Gasoline ・ Nerve biopsy ・ Nerve block ・ Nerve center ・ Nerve centre ・ Nerve Centre (organisation) ・ Nerve compression syndrome ・ Nerve conduction study ・ Nerve conduction velocity ・ Nerve cord ・ Nerve Damage ・ Nerve Engine ・ Nerve fascicle ・ Nerve fiber ・ Nerve fiber layer ・ Nerve Filter ・ Nerve growth factor ・ Nerve growth factor IB ・ Nerve growth factor receptor ・ Nerve guidance conduit ・ Nerve induction ・ Nerve injury ・ Nerve Net ・ Nerve net ・ Nerve of a covering ・ Nerve of Latarjet ・ Nerve of pterygoid canal ・ Nerve of Wrisberg Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Nerve fiber ： ウィキペディア英語版 Nerve fiber A nerve fiber is a threadlike extension of a nerve cell and consists of an axon and (in some cases) a myelin sheath. There are nerve fibers in the central nervous system and peripheral nervous system. In the central nervous system (CNS), myelin is produced by oligodendroglia cells. Schwann cells form myelin in the peripheral nervous system (PNS). Schwann cells can also make a thin covering for an axon which does not consist of myelin (in the PNS). A peripheral nerve fiber consists of an axon, myelin sheath, Schwann cells and its endoneurium. There are no endoneurium and Schwann cells in the central nervous system. ==Central nerve fibers== In the central nervous system, nerve fibers differ in terms of size, conduction velocity, and presence or lack of myelin. For example, the olfactory nerve fibers are short and without myelin, but the optic nerve fibers are myelinated (the olfactory and optic nerves are considered as a parts of the CNS, while other cranial nerves are a component of the PNS). A bundle of nerve fibers constitutes a tract in the central nervous system. The pyramidal tract and extrapyramidal tracts have long nerve fibers that descend from the brain to the spinal cord. These fibers have an important role in motor control, and are known as descending tracts. There are other bundles of nerve fibers in the CNS that are called ascending tracts.These carry sensory information from the periphery to the different areas of the brain (such as the cerebral cortex, cerebellum, and brain stem). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nerve fiber」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.