mýelínslíðinn

Mýelínslíðinn is the Icelandic term for myelin sheath. The myelin sheath is a fatty, insulating layer that surrounds nerve fibers (axons) in the central and peripheral nervous systems. It is produced by specialized cells: oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. The myelin sheath is not continuous but 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, also known as action potentials, travel along the axon. This insulation allows the electrical signal to "jump" from one node of Ranvier to the next, a process called saltatory conduction. This significantly speeds up neural communication compared to unmyelinated axons. Myelin also plays a role in supporting and protecting the axon.

Damage to the myelin sheath, a process known as demyelination, can lead to a variety of neurological disorders. Conditions like multiple sclerosis (MS) are characterized by the immune system attacking and destroying myelin in the central nervous system, resulting in impaired nerve function and a range of symptoms. Similarly, Guillain-Barré syndrome affects the myelin sheath in the peripheral nervous system. The composition of myelin includes lipids and proteins, and its integrity is crucial for efficient and healthy nerve function.