müeliinikestade

Myelin sheath is a fatty insulating layer that surrounds the axons of neurons in the central and peripheral nervous systems. This sheath is composed of glial cells, specifically 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. This segmented structure is crucial for the efficient transmission of electrical impulses along the axon.

The primary function of the myelin sheath is to increase the speed of nerve impulse conduction. The fatty nature of myelin acts as an electrical insulator, preventing the leakage of electrical current from the axon. This insulation allows the action potential, the electrical signal that travels down the neuron, to jump from one node of Ranvier to the next, a process known as saltatory conduction. Without myelin, nerve impulses would travel much slower, significantly impairing communication within the nervous system.

In addition to speeding up signal transmission, myelin also plays a role in protecting and supporting the axon. It helps to maintain the structural integrity of the axon and can contribute to axonal regeneration after injury. Diseases that damage or destroy the myelin sheath, such as multiple sclerosis, can lead to a wide range of neurological symptoms, including loss of sensation, muscle weakness, and coordination problems, highlighting the critical importance of this specialized structure for proper nervous system function.