What causes myelination to occur?

When a peripheral axon at least 1 to 2 µm in diameter triggers myelination, a Schwann cell wraps many layers of tightly packed cell membrane around a single segment of that axon.

Why is myelination of axons important?

Its main function, however, is to insulate the axon and increase the velocity of action potential propagation. Myelin has properties of low capacitance and high electrical resistance which means it can act as an insulator. Therefore, myelin sheaths insulate axons to increase the speed of electrical signal conduction.

Are peripheral nerves myelinated?

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.

What is the purpose of a myelin sheath quizlet?

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. If myelin is damaged, these impulses slow down.

What cell type is responsible for myelination in the PNS?

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 to the nervous system functions of all the neurons are myelinated?

1. If axons of all neurons were myelinated, nerve signals would be transmitted at higher speeds in fibers that are ordinarily unmyelinated.

Why does an action potential happen faster on a myelinated neuron than an Unmyelinated neuron?

Action potential propagation in myelinated neurons is faster than in unmyelinated neurons because of saltatory conduction.

Why does myelin decrease capacitance?

Myelin reduces membrane capacitance by increasing the thickness of the membrane (increase in separation of cations and anions) and by decreasing the amount of charge stored on both sides of the membrane.