myelinového

Myelin is a fatty insulating layer that surrounds nerve fibers, called axons, in the vertebrate nervous system. It is produced by glial cells: oligodendrocytes in the central nervous system (brain and spinal cord) and Schwann cells in the peripheral nervous system (nerves outside the brain and spinal cord). The myelin sheath is not continuous; it is interrupted at regular intervals by gaps called nodes of Ranvier.

The primary function of myelin is to speed up the transmission of electrical signals along the axon. This is achieved through a process called saltatory conduction, where the action potential "jumps" from one node of Ranvier to the next, rather than propagating continuously along the entire length of the axon. This significantly increases the speed of nerve impulse conduction, allowing for rapid and efficient communication between different parts of the nervous system.

Myelin also plays a role in protecting and supporting the axon. The lipid-rich myelin sheath provides a physical barrier and helps to maintain the structural integrity of the axon. In addition, the metabolic support provided by the glial cells that produce myelin is crucial for the long-term health and function of the axon.

Demyelination, the loss of myelin, can have severe consequences for nervous system function. Diseases such as multiple sclerosis are characterized by the progressive destruction of myelin, leading to a wide range of neurological symptoms including weakness, sensory disturbances, and coordination problems. Damage to myelin can also occur due to trauma or other neurological conditions. The regeneration of myelin, known as remyelination, can sometimes occur and may help to restore function, although its effectiveness can vary.