Neurilemma: Difference between revisions

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{{Short description|The outermost layer of the nerve fiber in the peripheral nervous system}}
Neurilemma


==Neurilemma==
The '''neurilemma''', also known as the '''sheath of Schwann''', is the outermost layer of the [[myelin sheath]] surrounding the [[axon]] of a [[neuron]]. It is essential for the proper functioning of the [[peripheral nervous system]] (PNS).
The '''neurilemma''', also known as the '''sheath of Schwann''', is the outermost layer of the [[myelinated]] or [[unmyelinated]] [[nerve fibers]] in the [[peripheral nervous system]] (PNS). It is formed by [[Schwann cells]], which are a type of [[glial cell]] that play a crucial role in the maintenance and regeneration of [[peripheral nerves]].


==Structure==
==Structure==
The neurilemma is a thin, delicate membrane that envelops the axon of a nerve cell. In myelinated nerve fibers, the neurilemma is the outermost layer of the [[myelin sheath]], which is composed of multiple layers of Schwann cell membrane wrapped around the axon. In unmyelinated fibers, the neurilemma still surrounds the axon, but without the multiple layers of myelin.
[[File:Gray631.png|thumb|right|Diagram of a neuron showing the neurilemma.]]
 
The neurilemma is formed by [[Schwann cells]], which are a type of [[glial cell]] in the PNS. These cells wrap around the axon, creating a protective and insulating layer. The neurilemma is the outermost layer of this wrapping and contains the nucleus and cytoplasm of the Schwann cell.
[[File:Neuron with Schwann cell.png|thumb|right|Diagram of a neuron with a Schwann cell forming the myelin sheath and neurilemma.]]


==Function==
==Function==
The primary function of the neurilemma is to protect and insulate nerve fibers, facilitating the rapid transmission of [[nerve impulses]] along the axon. Additionally, the neurilemma plays a vital role in the regeneration of damaged nerve fibers. When a peripheral nerve is injured, the neurilemma provides a pathway for the regrowth of the axon, allowing for the potential recovery of nerve function.
The primary function of the neurilemma is to protect the axon and aid in the regeneration of damaged nerve fibers. Unlike the [[central nervous system]] (CNS), where [[oligodendrocytes]] form the myelin sheath, the PNS has the ability to regenerate damaged axons, largely due to the presence of the neurilemma.


==Regeneration==
==Role in Nerve Regeneration==
Unlike the [[central nervous system]] (CNS), where nerve regeneration is limited, the PNS has a greater capacity for repair and regeneration, largely due to the presence of the neurilemma. Schwann cells within the neurilemma secrete growth factors and form a regeneration tube that guides the regrowing axon to its target.
When a nerve fiber is damaged, the neurilemma plays a crucial role in the repair process. It forms a regeneration tube that guides the growth of the new axon, allowing it to reconnect with its target cells. This regenerative capability is a key difference between the PNS and the CNS, where such regeneration is limited.


==Clinical Significance==
==Clinical Significance==
Damage to the neurilemma can result in impaired nerve function and delayed or incomplete nerve regeneration. Conditions such as [[neuropathy]] and [[nerve compression syndromes]] can affect the integrity of the neurilemma, leading to symptoms such as pain, numbness, and muscle weakness.
Damage to the neurilemma can result in impaired nerve function and delayed healing of nerve injuries. Conditions such as [[Guillain-Barré syndrome]] and [[Charcot-Marie-Tooth disease]] can affect the neurilemma, leading to neurological symptoms.


==Related pages==
==Related pages==
* [[Myelin]]
* [[Schwann cell]]
* [[Schwann cell]]
* [[Myelin sheath]]
* [[Peripheral nervous system]]
* [[Peripheral nervous system]]
* [[Axon]]
* [[Nerve regeneration]]
* [[Nerve regeneration]]
* [[Glial cell]]


[[Category:Neuroanatomy]]
[[Category:Neuroanatomy]]
[[Category:Peripheral nervous system]]

Latest revision as of 14:08, 21 February 2025

Neurilemma

The neurilemma, also known as the sheath of Schwann, is the outermost layer of the myelin sheath surrounding the axon of a neuron. It is essential for the proper functioning of the peripheral nervous system (PNS).

Structure[edit]

Diagram of a neuron showing the neurilemma.

The neurilemma is formed by Schwann cells, which are a type of glial cell in the PNS. These cells wrap around the axon, creating a protective and insulating layer. The neurilemma is the outermost layer of this wrapping and contains the nucleus and cytoplasm of the Schwann cell.

Function[edit]

The primary function of the neurilemma is to protect the axon and aid in the regeneration of damaged nerve fibers. Unlike the central nervous system (CNS), where oligodendrocytes form the myelin sheath, the PNS has the ability to regenerate damaged axons, largely due to the presence of the neurilemma.

Role in Nerve Regeneration[edit]

When a nerve fiber is damaged, the neurilemma plays a crucial role in the repair process. It forms a regeneration tube that guides the growth of the new axon, allowing it to reconnect with its target cells. This regenerative capability is a key difference between the PNS and the CNS, where such regeneration is limited.

Clinical Significance[edit]

Damage to the neurilemma can result in impaired nerve function and delayed healing of nerve injuries. Conditions such as Guillain-Barré syndrome and Charcot-Marie-Tooth disease can affect the neurilemma, leading to neurological symptoms.

Related pages[edit]