myelinated nerve fiber
Noun A nerve fiber that is encased in a sheath of myelin. Myelin is a fatty, insulating substance that surrounds the axon of certain neurons, significantly increasing the speed at which electrical impulses (nerve signals) travel along the fiber.
The term is used in biological, medical, and anatomical contexts to describe a specific type of neuronal structure. It is a precise, technical term.
Examples * Under the microscope, the myelinated nerve fiber appeared distinctly white due to its fatty sheath. * The rapid reflex was mediated by signals traveling along myelinated nerve fibers. * Diseases like multiple sclerosis damage the myelin sheath, impairing the function of myelinated nerve fibers.
- In contrast to unmyelinated fibers: The term is often used in comparative anatomy and physiology to distinguish fast-conducting myelinated fibers from slower, unmyelinated nerve fibers.
- Example: "Pain signals are often carried by unmyelinated fibers, while motor commands travel via myelinated nerve fibers."
- Myelinated (Adjective): Describing a nerve fiber that has a myelin sheath.
- Example: "a myelinated axon"
- Myelination (Noun): The process of forming a myelin sheath around a nerve fiber.
- Myelin sheath (Noun): The insulating covering itself.
- Unmyelinated nerve fiber (Noun): A nerve fiber lacking a myelin sheath.
- Medullated nerve fiber (an older, synonymous term)
The core meaning is specific and anatomical. There are no common idioms, phrasal verbs, or significantly different meanings associated with this precise compound term. Its understanding is dependent on the components "myelinated" (having myelin) and "nerve fiber" (the axon of a neuron).
- a nerve fiber encased in a sheath of myelin