Myelinated nerve fibers

Myelinated Nerve Fibers

Myelinated nerve fibers are a type of nerve fiber that is covered with a protective myelin sheath. This sheath is crucial for the proper functioning of the nervous system as it increases the speed at which electrical impulses propagate along the nerve fiber.

Structure

The myelin sheath is composed of multiple layers of lipid and protein that wrap around the axon of the nerve cell. This structure is formed by Schwann cells in the peripheral nervous system and by oligodendrocytes in the central nervous system.

Function

The primary function of myelinated nerve fibers is to facilitate rapid transmission of action potentials along the axon. This is achieved through a process known as saltatory conduction, where the electrical impulse "jumps" from one node of Ranvier to the next, significantly increasing conduction velocity compared to unmyelinated fibers.

Importance in the Nervous System

Myelinated nerve fibers are essential for the efficient functioning of the nervous system. They are involved in the transmission of sensory and motor information, enabling quick reflexes and coordinated movements. Damage to the myelin sheath, as seen in conditions like multiple sclerosis, can lead to severe neurological deficits.

Clinical Significance

Demyelination, or the loss of the myelin sheath, can result in various neurological disorders. Multiple sclerosis is one of the most well-known demyelinating diseases, where the immune system attacks the myelin sheath, leading to impaired nerve function. Other conditions include Guillain-Barré syndrome and Charcot-Marie-Tooth disease.

See Also

• Nerve fiber
• Axon
• Neurotransmission
• Peripheral nervous system
• Central nervous system

References

,

 The pathophysiology of multiple sclerosis: the mechanisms underlying the production of symptoms and the natural history of the disease, 
 Philosophical Transactions of the Royal Society B: Biological Sciences, 
 1999, 
 Vol. 354(Issue: 1390), 
 pp. 1649–1673, 
 DOI: 10.1098/rstb.1999.0510,

SG,

 Clinical Neuroanatomy, 
 28th edition, 
 McGraw-Hill Education, 
 2017, 
  
  
 ISBN 978-0071847704,

External Links

• National Institute of Neurological Disorders and Stroke - Multiple Sclerosis