Difference Between Schwann Cell and Myelin Sheath

Myelin is formed by Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS). Each Schwann cell forms a single myelin sheath around an axon. In contrast, each oligodendrocyte forms multiple sheaths (up to 30 or more) around different axons (Figure 1).

1. Are Schwann cells myelin sheath?
2. What are the gaps between Schwann cells and their myelin sheaths called?
3. What is the difference between myelin sheath and Neurilemma?
4. Do Schwann cells produce myelin?
5. What would happen if there were no Schwann cells?
6. What is the main function of Schwann cells?
7. What are the gaps in the myelin sheath?
8. What is the function of myelin sheath?
9. What happens if myelin sheath is damaged?
10. What is a Neurolemma?
11. What is a Neurilemma?
12. What are nodes of Ranvier?

Are Schwann cells myelin sheath?

Schwann cell, also called neurilemma cell, any of the cells in the peripheral nervous system that produce the myelin sheath around neuronal axons. ... These cells are equivalent to a type of neuroglia called oligodendrocytes, which occur in the central nervous system.

What are the gaps between Schwann cells and their myelin sheaths called?

Gaps between adjacent Schwann cells of a myelin sheath are known as nodes of Ranvier.

What is the difference between myelin sheath and Neurilemma?

The key difference between Neurilemma and the myelin sheath is that Neurilemma is the cytoplasm and the nuclei of the Schwann cells lying outside the myelin sheath while Myelin sheath is a modified cellular membrane wrapped around the axon of the neurons.

Do Schwann cells produce myelin?

Schwann cells make myelin in the peripheral nervous system (PNS: nerves) and oligodendrocytes in the central nervous system (CNS: brain and spinal cord). In the PNS, one Schwann cell forms a single myelin sheath (Figure 1A).

What would happen if there were no Schwann cells?

What would happen if there were no Schwann cells? A) Muscles would not be able to contract and the body would be paralyzed.

What is the main function of Schwann cells?

Schwann cells (SCs) are the major glial cell type in the peripheral nervous system. They play essential roles in the development, maintenance, function, and regeneration of peripheral nerves. In the mature nervous system, SCs can be categorized into two major classes: myelinating and nonmyelinating cells.

What are the gaps in the myelin sheath?

The glial cells forming myelin sheaths are called oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. The gaps (approximately 1micrometer wide) formed between myelin sheath cells long the axons are called Nodes of Ranvier.

What is the function of myelin sheath?

Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.

What happens if myelin sheath is damaged?

A demyelinating disease is any condition that results in damage to the protective covering (myelin sheath) that surrounds nerve fibers in your brain, optic nerves and spinal cord. When the myelin sheath is damaged, nerve impulses slow or even stop, causing neurological problems.

What is a Neurolemma?

Neurilemma (also known as neurolemma, sheath of Schwann, or Schwann's sheath) is the outermost nucleated cytoplasmic layer of Schwann cells (also called neurilemmocytes) that surrounds the axon of the neuron. It forms the outermost layer of the nerve fiber in the peripheral nervous system.

What is a Neurilemma?

: the plasma membrane surrounding a Schwann cell of a myelinated nerve fiber and separating layers of myelin.

What are nodes of Ranvier?

The nodes of Ranvier are characterized by short (1um), specialized regions in the axonal membrane that are not insulated by myelin. Although it is bare of myelin at the node, the axon is in direct contact with the microvilli of the Schwann cells in the PNS, or with processes of astrocytes in the CNS (Figure 1).