Myelin incisure

Myelin Incisure (also known as Schmidt-Lanterman incisures or clefts) are small, periodic interruptions in the myelin sheath of myelinated axons. They are named after the German anatomist, Otto Friedrich Karl Deiters, who first described them in 1865.

Structure

Myelin incisures are small gaps in the myelin sheath that occur at regular intervals along the length of a myelinated axon. They are formed by the Schwann cells that produce the myelin sheath, and are thought to play a role in the maintenance and repair of the sheath.

The incisures are filled with cytoplasm from the Schwann cell, and contain a number of organelles, including mitochondria and endoplasmic reticulum. They are connected to the outside of the sheath by a narrow channel known as a mesaxon.

Function

The exact function of myelin incisures is not fully understood, but they are thought to play a role in the maintenance and repair of the myelin sheath. They may also be involved in the transport of nutrients and waste products between the Schwann cell and the axon.

In addition, the incisures may play a role in the conduction of electrical signals along the axon. The presence of cytoplasm in the incisures may allow for the propagation of action potentials in a manner similar to the Nodes of Ranvier, although this is still a topic of ongoing research.

Clinical significance

Damage to the myelin sheath, such as that seen in multiple sclerosis, can disrupt the function of the myelin incisures and impair the conduction of electrical signals along the axon. This can lead to a range of neurological symptoms, including muscle weakness, numbness, and loss of coordination.

See also

• Myelin
• Schwann cell
• Nodes of Ranvier
• Multiple sclerosis

References

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  Gray's Anatomy illustration of a myelin incisure