What is the Difference Between Neurilemma and Myelin Sheath?

The main difference between the neurilemma and the myelin sheath lies in their location, structure, and function within the nervous system.

Neurilemma:

• Also known as neurolemma, sheath of Schwann, or Schwann's sheath.
• Formed by the outer cell membrane, cytoplasm, and nuclei of Schwann cells.
• Found only in the peripheral nervous system.
• Surrounds both myelinated and non-myelinated nerve fibers.
• Serves a protective function and is important for the regeneration process of nerves.

Myelin Sheath:

• A laminated sheath made up of lipoproteins.
• Formed by consecutive wrappings of Schwann cell membrane around the axon of a neuron.
• Found in both the central and peripheral nervous systems.
• Surrounds only myelinated nerve fibers.
• Protects and insulates the nerve fibers, increasing the rate of conduction of nerve impulses (saltatory conduction).

In summary, the neurilemma is a protective layer found only in the peripheral nervous system, while the myelin sheath is a protective and insulating layer found in both the central and peripheral nervous systems. The myelin sheath is formed by consecutive wrappings of Schwann cell membrane around the axon, whereas the neurilemma is formed by the outer cell membrane, cytoplasm, and nuclei of Schwann cells.

Comparative Table: Neurilemma vs Myelin Sheath

Here is a table comparing the differences between the neurilemma and the myelin sheath:

In summary, the neurilemma is a plasma membrane layer of Schwann cells found only in the peripheral nervous system, while the myelin sheath is a fatty layer that surrounds the nerve fiber and is found in both the central and peripheral nervous systems. The myelin sheath is formed by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system, and it protects and insulates the axon.