Neurilemma vs. Myelin Sheath

The human body is a complicated piece of art, and there are many parts about which confusion can arise because of their placement and usage. Neurilemma and Myelin Sheath are two such which have many differences between them, but the main one is that the nucleus and the cytoplasm that make the outermost layer of the Schwann cells and the one that surrounds the axon of the neuron is known as Neurilemma. While the part which is present on the surface and has a Neurilemma and makes sure that the nerves are able to function properly is called the Myelin Sheath.

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Neurilemma vs. Myelin Sheath

Contents: Difference between Neurilemma and Myelin Sheath

Comparison Chart

Basis of DistinctionNeurilemma Myelin Sheath
RoleThe primary function of Myelin Sheath is to protect the axon and the nerves.The primary role of Neurilemma is to safeguard the Myelin Sheath.
PresenceThe cytoplasm that makes the outermost layer of the Schwann cells.Part which is present on the surface and has a Neurilemma surface.
ExplanationThe nucleus and the cytoplasm that makes the outermost layer of the Schwann cells and the one that surrounds the axon of the neuron.An insulating box like structure that surrounds the nervous system and is closely placed to the neuron and the axons, and makes sure that the nerves are able to function properly.
FormationFormed in the Schwann cells in the peripheral nervous system.Formed by Schwann cells in the peripheral nervous system while they are formed by Oligodendrocytes in the central nervous system.
Existence

Present in the peripheral nervous system.

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Absent in the central nervous system.

Present in both the peripheral and central nervous system.

What is Neurilemma?

The simplest of definition for this term will be that the nucleus and the cytoplasm that make the outermost layer of the Schwann cells and the one that surrounds the axon of the neuron is known as Neurilemma. The main thing to remember about these is that they are only present in the peripheral nervous system because of the presence of their parent cell while they are absent in the central nervous system because there is no Schwann cell present there. It is considered critical for the reason that it helps in regeneration of the nerves which are lost due to various reasons. It is also thought that the lack of such cells in the nervous system is the cause that the regeneration cannot take place in the central nervous system. It has many functions that it performs if it is able to keep its place then it can serve as a guide to the axon so that the target is reached. Neurons are the cells which can get excited by a charge and therefore help in transmitting information from one part of the body to the brain and then from the brain to the other part of the body and for that process to complete these neurilemmas play a significant role. The parts that are protected by its presence as the outermost layer include Myelin Sheath and the axons. Both have an important part to play for the neurons to function and the protection that is provided to them goes a long way to ensuring that they are able to operate correctly.

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What is Myelin Sheath?

This is the part which is present on the surface and has a Neurilemma surface protecting it. This is basically an insulating box like structure that surrounds the nervous system and is closely placed to the neuron and the axons, and makes sure that the nerves are able to function properly. It helps in transmitting the nerves impulses from the cell membrane of the Schwann cell and is also known as a medullary sheath. The primary purpose of it is to act as an electrical insulator which increases the speed of information that has to move from one part to the other such as muscles. It is formed by the wrapping of Schwann cells around the axon of the neuron. In the peripheral nervous system, these are produced with the help of these cells while in the central nervous system myelin sheath are created with the support of oligodendrocytes but have the same function irrespective of how they have originated. In the peripheral nervous system, they assist in producing the nerve fibers while in the central nervous system they produce a white colored matter which both end up protecting the axon and insulate it. They are also called the nodes of Ranvier because they are interrupted a lot throughout the system because of the nerve fiber that they produce. They are dependent on the Neurilemma for protection, but the latter one is not dependent on it in any way and therefore can be considered less superior in comparison though it does perform more functions.

Key Differences between Neurilemma and Myelin Sheath

  1. Neurilemma is the cytoplasm that makes the outermost layer of the Schwann cells while Myelin Sheath is the part which is present on the surface and has a Neurilemma surface.
  2. The primary role of Myelin Sheath is to protect the axon and the nerves while the central function of Neurilemma is to safeguard the Myelin Sheath.
  3. The nucleus and the cytoplasm that make the outermost layer of the Schwann cells and the one that surrounds the axon of the neuron is known as Neurilemma.
  4. Myelin Sheath is an insulating box like structure that surrounds the nervous system and is closely placed to the neuron and the axons, and makes sure that the nerves are able to function properly.
  5. The Neurilemma is formed in the Schwann cells in the peripheral nervous system. One the other hand, Myelin Sheath is formed by Schwann cells in the peripheral nervous system while they are formed by Oligodendrocytes in the central nervous system.
  6. Neurilemma is present in the peripheral nervous system while they are absent in the central nervous system. On the other hand, Myelin Sheath is present in both the peripheral and central nervous system.
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