Myelin

MY-uh-lin /ˈmaɪəlɪn/
nounC1GRE
formalscientific

A mixture of proteins and phospholipids forming a whitish insulating sheath around many nerve fibers, increasing the speed at which impulses are conducted.

Crucial for rapid and efficient nerve impulse transmission, acting like insulation on an electrical wire.

The story behind the word. The word 'myelin' comes from the Greek word 'myelos,' meaning 'marrow.' This is because the substance was initially thought to resemble bone marrow due to its fatty, whitish appearance. It was first used in the mid-19th century to describe the fatty substance surrounding nerve fibers.

Word relationships

  • nerve insulation: A descriptive, non-technical term; 'myelin' is the precise scientific term.

Word family

  • myelinated (adjective): Having a myelin sheath.
  • demyelination (noun): The loss of the myelin sheath.

Collocations

  • myelin sheath
  • myelin damage
  • myelin repair
  • form myelin

Example sentences

  • "In multiple sclerosis, the protective myelin sheath around nerve fibers is damaged, disrupting communication." Neurological disorder
  • "The process of myelin formation, or myelination, continues well into adulthood, especially in areas related to complex cognition." Brain development

Memory hook

MYELIN makes signals 'MY-LEAP-IN' speed – it helps impulses leap quickly. My leap in speed

When not to use

Do not use 'myelin' for any insulating material; it refers specifically to the biological sheath around axons.

Fun facts

  • Myelin is produced by two types of glial cells: oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system.
  • The 'white matter' of the brain and spinal cord gets its color from the fatty myelin sheaths.

Related words

Axon, Neuron

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