Myelinisoituvat

Myelinisoituvat is a term used to describe the process by which nerve fibers acquire a myelin sheath, the lipid-rich insulating layer surrounding axons. In humans, myelination begins before birth in some regions and continues through childhood and adolescence, with regional variation in timing and extent.

In the central nervous system, oligodendrocytes extend processes that wrap around several axons to form compact myelin segments, separated by nodes of Ranvier. This arrangement enables saltatory conduction, greatly increasing the speed of electrical impulses and reducing metabolic demand on the neuron. Myelination patterns in the CNS are developmentally regulated and adapt to functional needs.

In the peripheral nervous system, Schwann cells myelinate individual axons. Peripheral myelination supports rapid signal transmission and also plays a role in axon regeneration after injury, though remyelination can be incomplete.

Myelin consists of a lipid-rich membrane with specific proteins that stabilize and insulate the sheath. In the CNS, key myelin proteins include myelin basic protein (MBP) and proteolipid protein (PLP); in the PNS, major proteins include P0 and PMP22. The integrity of myelin is essential for efficient nerve signaling and long-term neural health.

Disorders of myelination can be hypomyelinating (reduced formation) or demyelinating (loss of myelin). Examples include multiple sclerosis (CNS demyelination) and various leukodystrophies (developmental myelin disorders). Imaging and research of myelin dynamics aid diagnosis and understanding of neurodevelopment and neurodegeneration, including the capacity for remyelination.