myelinelaag

Myelinelaag is a term used in some contexts to refer to the myelin layer that surrounds axons in the nervous system. In mainstream neuroscience, the standard term is the myelin sheath, and myelinelaag is not widely used outside particular linguistic or historical contexts. The term may appear in some Dutch-language sources or early literature as a descriptor for the insulating coating produced by glial cells.

The myelin layer is formed by glial cells: oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. Each glial cell wraps its membrane around segments of an axon, creating multiple compact layers rich in lipids and specific proteins. Gaps between adjacent myelin segments, known as nodes of Ranvier, facilitate rapid electrical signaling.

Functionally, the myelin layer increases conduction velocity and efficiency of nerve impulses through saltatory conduction. By reducing membrane capacitance and increasing resistance, it allows action potentials to travel quickly along the axon with less energy expenditure. The integrity of the myelin layer is essential for normal neurological function.

Development, maintenance, and pathology are important aspects of the myelin layer. Myelination begins in prenatal development and continues into adolescence, influenced by neuronal activity and growth factors. Demyelinating diseases, such as multiple sclerosis and Guillain-Barré syndrome, damage the myelin layer and slow or block nerve conduction. Remyelination can occur, but its extent varies and may be incomplete.

Etymology reflects the idea of a layered covering, with “myelin” referring to the lipid-rich insulation and “laag” (layer) denoting a structural coating. While informative, the term myelinelaag remains less common than “myelin sheath” in contemporary usage.