Myelin is a noun that refers to a protective sheath or covering made up of lipids and proteins that surrounds and insulates nerve fibers in the central nervous system (CNS) and peripheral nervous system (PNS) of animals, including humans. It is a vital component of the nervous system, essential for the proper functioning of nerve cells.
This fatty substance helps to enhance the speed and efficiency of nerve impulse transmission by acting as an electrical insulator. It forms a whitish, fatty layer around nerve fibers, progressively coating and wrapping them. This myelin sheath helps to protect and isolate the nerve fibers, preventing electrical impulses from being dissipated and minimizing interference between adjacent nerve fibers.
The myelin sheath is primarily composed of a type of glial cell called oligodendrocytes in the CNS, and Schwann cells in the PNS. Both types of cells wrap themselves around the nerve fibers multiple times, forming concentric layers of myelin. The gaps between these myelin sheaths are referred to as nodes of Ranvier, which help to facilitate the rapid conduction of nerve impulses.
Damage or loss of myelin can disrupt the proper functioning of nerve cells, leading to various neurological disorders. Conditions such as multiple sclerosis (MS) are characterized by the destruction or degeneration of myelin in the CNS, resulting in impaired nerve signal transmission and a range of symptoms including mobility issues, sensory disturbances, and cognitive impairment.
In summary, myelin is a fatty substance that surrounds and insulates nerve fibers, facilitating efficient electrical impulse transmission and protecting neural connections within the nervous system.
