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  2. Grey matter - Wikipedia

    en.wikipedia.org/wiki/Grey_matter

    Grey matter is distinguished from white matter in that it contains numerous cell bodies and relatively few myelinated axons, while white matter contains relatively few cell bodies and is composed chiefly of long-range myelinated axons. [1] The colour difference arises mainly from the whiteness of myelin. In living tissue, grey matter actually ...

  3. Myelin - Wikipedia

    en.wikipedia.org/wiki/Myelin

    Myelin (/ ˈ m aɪ. ə l ɪ n / MY-ə-lin) is a lipid-rich material that surrounds nerve cell axons to insulate them and increase the rate at which electrical impulses (called action potentials) pass along the axon. [1] [2] The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However ...

  4. Group A nerve fiber - Wikipedia

    en.wikipedia.org/wiki/Group_A_nerve_fiber

    Group A are heavily myelinated, group B are moderately myelinated, and group C are unmyelinated. [1] [2] The other classification is a sensory grouping that uses the terms type Ia and type Ib, type II, type III, and type IV, sensory fibers. [1]

  5. White matter - Wikipedia

    en.wikipedia.org/wiki/White_matter

    White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons, also called tracts. [1] Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain ...

  6. Axon - Wikipedia

    en.wikipedia.org/wiki/Axon

    There are two types of axons in the nervous system: myelinated and unmyelinated axons. [5] Myelin is a layer of a fatty insulating substance, which is formed by two types of glial cells: Schwann cells and oligodendrocytes. In the peripheral nervous system Schwann cells form the myelin sheath of a myelinated axon. Oligodendrocytes form the ...

  7. Oligodendrocyte - Wikipedia

    en.wikipedia.org/wiki/Oligodendrocyte

    A single oligodendrocyte can extend its processes to cover up to 40 axons, that can include multiple adjacent axons. [2] The myelin sheath is not continuous but is segmented along the axon's length at gaps known as the nodes of Ranvier. In the peripheral nervous system the myelination of axons is carried out by Schwann cells. [1]

  8. Nervous tissue - Wikipedia

    en.wikipedia.org/wiki/Nervous_tissue

    Myelinated axons (right) conduct impulses faster than unmyelinated axons. The function of nervous tissue is to form the communication network of the nervous system by conducting electric signals across tissue. [13] In the CNS, grey matter, which contains the synapses, is important for information processing.

  9. Nervous system - Wikipedia

    en.wikipedia.org/wiki/Nervous_system

    Gray matter (which is only gray in preserved tissue, and is better described as pink or light brown in living tissue) contains a high proportion of cell bodies of neurons. White matter is composed mainly of myelinated axons, and takes its color from the myelin. White matter includes all of the nerves, and much of the interior of the brain and ...