How is myelination different in PNS and CNS?
How is myelination different in PNS and CNS?
CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function — to promote efficient transmission of a nerve impulse along the axon.
What is the main difference between Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system?
The primary difference is their location. Oligodendrocytes myelinate the central nervous system, while Schwann cells myelinate the peripheral nervous system. Oligodendrocytes are also capable of myelinating multiple axons, while Schwann cells can only myelinate one axon per cell.
Are all neurons in the PNS and CNS myelinated?
Myelin is formed in the central nervous system (CNS; brain, spinal cord and optic nerve) by glial cells called oligodendrocytes and in the peripheral nervous system (PNS) by glial cells called Schwann cells….
| Myelin | |
|---|---|
| Neuron with oligodendrocyte and myelin sheath in the CNS | |
| Details | |
| System | Nervous system |
| Identifiers |
How is myelin formed in the PNS and CNS?
Myelin is formed in the PNS (peripheral nervous system) and CNS by the innermost sheet-like glial process in contact with the axon spiraling around it and spinning out multiple layers of overlapping membrane. Cytoplasm becomes expelled from all but the innermost and outermost layers of the myelin sheath.
Why is myelination typically a feature of neurons in the PNS?
Myelin can greatly increase the speed of electrical impulses in neurons because it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length.
Why are many of the neurons in the peripheral nervous system myelinated?
Myelin sheath is wrapped around the axons of neurons in both central and peripheral nervous systems. This is called myelination. Myelination provides the electrical insulation of neurons.
What are Schwann cells of the PNS and myelination?
Schwann cells are also known as neurolemmocytes, and have two types of formations. They may form a thick sheath of myelin or create indented plasma membrane folds around peripheral axons throughout the PNS. Where a Schwann cell covers an axon, the outer Schwann cell surface is known as the neurilemma.
What forms myelin in the PNS?
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).
What produces myelin in the PNS?
Peripheral nervous system (PNS) myelin is formed by the differentiation of the plasma membrane of Schwann cells. One of the biochemical characteristics that distinguishes myelin from other biological membranes is its high lipid-to-protein ratio.
Are all peripheral nerves myelinated?
Normal Anatomy and MRI Appearance. The fundamental unit of a peripheral nerve is the axon, which may be either myelinated or unmyelinated, and which carries efferent (motor) or afferent (sensory) electrical impulses. Peripheral nerves have a mixture of myelinated and unmyelinated axons.
