What does myelin mean?
Definitions for myelin
ˈmaɪ ə lɪnmyelin
This dictionary definitions page includes all the possible meanings, example usage and translations of the word myelin.
Princeton's WordNet
myelin, myeline, medullanoun
a white fatty substance that forms a medullary sheath around the axis cylinder of some nerve fibers
Wiktionary
myelinnoun
A white, fatty material, composed of lipids and lipoproteins, that surrounds the axons of nerves.
Etymology: From μυελός + -in
Wikipedia
Myelin
Myelin is a lipid-rich material that surrounds nerve cell axons (the nervous system's "wires") to insulate them and increase the rate at which electrical impulses (called action potentials) are passed along the axon. The myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. However, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon. Rather, myelin sheaths the nerve in segments: in general, each axon is encased with multiple long myelinated sections with short gaps in between called nodes of Ranvier. Myelin is formed in the central nervous system (CNS; brain, spinal cord and optic nerve) by glial cells called oligodendrocytes and in the peripheral nervous system (PNS) by glial cells called Schwann cells. In the CNS, axons carry electrical signals from one nerve cell body to another. In the PNS, axons carry signals to muscles and glands or from sensory organs such as the skin. Each myelin sheath is formed by the concentric wrapping of an oligodendrocyte (CNS) or Schwann cell (PNS) process (a limb-like extension from the cell body) around the axon. Myelin reduces the capacitance of the axonal membrane. On a molecular level, in the internodes it increases the distance between extracellular and intracellular ions, reducing the accumulation of charges. The discontinuous structure of the myelin sheath results in saltatory conduction, whereby the action potential "jumps" from one node of Ranvier, over a long myelinated stretch of the axon called the internode, before "recharging" at the next node of Ranvier, and so on, until it reaches the axon terminal. Nodes of Ranvier are the short (c. 1 micron) unmyelinated regions of the axon between adjacent long (c. 0.2 mm – >1 mm) myelinated internodes. Once it reaches the axon terminal, this electrical signal provokes the release of a chemical message or neurotransmitter that binds to receptors on the adjacent post-synaptic cell (e.g., nerve cell in the CNS or muscle cell in the PNS) at specialised regions called synapses. This "insulating" role for myelin is essential for normal motor function (i.e. movement such as walking), sensory function (e.g. hearing, seeing or feeling the sensation of pain) and cognition (e.g. acquiring and recalling knowledge), as demonstrated by the consequences of disorders that affect it, such as the genetically determined leukodystrophies; the acquired inflammatory demyelinating disorder, multiple sclerosis; and the inflammatory demyelinating peripheral neuropathies. Due to its high prevalence, multiple sclerosis, which specifically affects the central nervous system (brain, spinal cord and optic nerve), is the best known disorder of myelin.
ChatGPT
myelin
Myelin is a fatty substance that surrounds and insulates the axons of nerve cells, allowing for efficient conduction of electrical signals within the nervous system. It is crucial for the proper functioning of the nervous system and is produced by specialized cells called oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.
Webster Dictionary
Myelinnoun
a soft white substance constituting the medullary sheats of nerve fibers, and composed mainly of cholesterin, lecithin, cerebrin, albumin, and some fat
Myelinnoun
one of a group of phosphorized principles occurring in nerve tissue, both in the brain and nerve fibers
Wikidata
Myelin
Myelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. It is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination. In humans, the production of myelin begins in the 14th week of fetal development, although little myelin exists in the brain at the time of birth. During infancy, myelination occurs quickly and continues through the adolescent stages of life. Schwann cells supply the myelin for peripheral neurons, whereas oligodendrocytes, specifically of the interfascicular type, myelinate the axons of the central nervous system. Myelin is considered a defining characteristic of the vertebrates, but myelin-like sheaths have also arisen by parallel evolution in some invertebrates, although they are quite different from vertebrate myelin at the molecular level. Myelin was discovered in 1854 by Rudolf Virchow.
Editors Contribution
myelin
A type of matter.
Myelin is essential for the proper functioning of our bodily systems.
Submitted by MaryC on January 16, 2017
Numerology
Chaldean Numerology
The numerical value of myelin in Chaldean Numerology is: 1
Pythagorean Numerology
The numerical value of myelin in Pythagorean Numerology is: 6
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"myelin." Definitions.net. STANDS4 LLC, 2024. Web. 25 Apr. 2024. <https://www.definitions.net/definition/myelin>.
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