What is myelin? What does it do? Which cells provide it in the central nervous system?
What is myelin? What does it do? Which cells provide it in the central nervous system?
Answer
Myelin is a fatty substance that forms a protective sheath around the axons of neurons. It is composed primarily of lipids and proteins and serves several important functions in the nervous system.
Functions of Myelin:
- Insulation: Myelin acts as an insulator for axons, preventing the loss of electrical signals as they travel along the nerve fibers. This insulation is crucial for maintaining the efficiency of signal transmission.
- Increased Conduction Velocity: Myelination allows for faster conduction of action potentials along the axon through a process called saltatory conduction. In this process, the action potential jumps from one node of Ranvier (gaps in the myelin sheath) to another, significantly speeding up the transmission of electrical impulses.
- Support and Protection: Myelin provides structural support to axons and protects them from damage. It also plays a role in the maintenance and repair of axonal integrity.
Cells that Provide Myelin in the Central Nervous System:
In the central nervous system (CNS), myelin is produced by oligodendrocytes. Each oligodendrocyte can extend its processes to multiple axons, wrapping around them to form the myelin sheath. This is in contrast to the peripheral nervous system (PNS), where myelin is produced by Schwann cells, with each Schwann cell myelinating a single axon.
In summary, myelin is a crucial component of the nervous system that enhances the speed and efficiency of electrical signal transmission, and it is provided by oligodendrocytes in the CNS
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