myelin
UK[ˈmaɪ.ə.lɪn]US[ˈmaɪ.ə.lɪn]
n
A white, fatty substance that forms a sheath around the axons of many nerve cells, enabling the rapid transmission of electrical impulses.
Morpheme Breakdown
myel
in
myel
marrow
in
chemical/biological substance suffix
Etymology
The word 'myelin' is a modern scientific term coined in the 19th century from Greek components. Its first element, myel-, derives from the Greek myelos, meaning "marrow," reflecting the substance's soft, fatty, core-like appearance when observed within nerve fibers. The suffix -in is a standard formative in biochemistry for naming neutral organic compounds. Thus, the term's literal construction as "marrow-like substance" logically describes the insulating material that forms the essential core sheathing of nerve axons, drawing a direct analogy from the soft center of bones to the vital inner coating of neural pathways.
Analysis
Structure: myel (marrow) + in (chemical/biological substance suffix)
myel (from Greek myelos, meaning "marrow, the innermost part"); in (a suffix of Greek and Latin origin used in scientific terminology to form names of substances, especially proteins or other organic compounds).
Examples
The degeneration of the myelin sheath is a hallmark of multiple sclerosis.
Myelin acts as an electrical insulator, greatly increasing the speed of nerve signal conduction.
Oligodendrocytes are the cells responsible for producing myelin in the central nervous system.