mýelínslíðisins

Myelínslíðisins is the Icelandic term for myelin sheath. The myelin sheath is a fatty insulating layer that surrounds nerve fibers, also known as axons, in the nervous system. This sheath is produced by glial cells: Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system. The myelin sheath is not continuous; it is interrupted at regular intervals by gaps called nodes of Ranvier.

The primary function of the myelin sheath is to increase the speed at which nerve impulses, or action potentials, travel along the axon. This is achieved through a process called saltatory conduction, where the electrical signal jumps from one node of Ranvier to the next. This significantly speeds up neural communication, allowing for rapid responses and complex cognitive functions. Myelination also plays a role in protecting the axon and providing metabolic support.

Disruption or damage to the myelin sheath, a condition known as demyelination, can lead to severe neurological disorders. Diseases like multiple sclerosis (MS) and Guillain-Barré syndrome are characterized by the immune system attacking and destroying the myelin. This damage impairs nerve signal transmission, resulting in symptoms such as muscle weakness, loss of sensation, coordination problems, and visual disturbances. The process of myelination, known as myelination, begins during fetal development and continues into early adulthood.