Nerve fibers

Japanese: 神経繊維 - しんけいせんい

A long axon extending from the cell body of a nerve cell. It is usually several millimeters to several centimeters long, but in the sciatic nerve, it can reach 1 meter. Functionally, they are broadly divided into motor fibers and sensory fibers. Structurally, they are classified as myelinated or unmyelinated depending on whether or not they have a coating called the myelin sheath that surrounds the axon, and both are found in large numbers in central and peripheral nerves. The speed of nerve conduction is faster in myelinated fibers. The myelin sheath has interruptions in places, called nodes of Ranvier. In peripheral nerves, regardless of whether they are myelinated or unmyelinated, a coating called the nerve sheath (Schwann's sheath) covers the outside. The origin and terminal parts of nerve fibers are bare fibers that lack both myelin and nerve sheaths. →Synapse/Neuron→Related topics Nerve | Nervous system | Schwannoma | Ganglion | Nerve plexus

Source : Heibonsha Encyclopedia About MyPedia Information

Japanese:

神経細胞の細胞体からのびた長い軸索突起。普通は数mmから数cmだが，座骨神経では1mに達するものもある。機能上は運動繊維と感覚繊維に大別。構造上は軸索を取り巻く髄鞘という被膜の有無によって有髄・無髄に区別され，そのいずれもが中枢および末梢神経に多数含まれている。神経伝導の速度は有髄繊維のほうが速い。髄鞘には所々に中断部があり，絞輪（ランビエ絞輪）と呼ばれる。また末梢神経では，有髄・無髄に関係なく，神経鞘（シュワン鞘）という被膜が外側をおおっている。神経繊維の起始部および末端部は，髄鞘・神経鞘をともに欠く裸繊維となっている。→シナプス／ニューロン
→関連項目神経｜神経系｜神経鞘腫｜神経節｜神経叢

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