Why does MS impair nervous system function?

MS is caused by damage to the myelin sheath. This sheath is the protective covering that surrounds nerve cells. When this nerve covering is damaged, nerve signals slow or stop. The nerve damage is caused by inflammation.

How does MS affect the nervous system?

MS occurs when the immune system attacks nerve fibers and myelin sheathing (a fatty substance which surrounds/insulates healthy nerve fibers) in the brain and spinal cord. This attack causes inflammation, which destroys nerve cell processes and myelin – altering electrical messages in the brain.

Why does multiple sclerosis only affect the central nervous system?

Myelin is present in the central nervous system (CNS) and peripheral nervous system (PNS); however only the central nervous system is affected by MS. CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells.

How does multiple sclerosis affect neurons and their function?

Multiple sclerosis affects neurons, the cells of the brain and spinal cord that carry information, create thought and perception, and allow the brain to control the body. Surrounding and protecting some of these neurons is a fatty layer known as the myelin sheath, which helps neurons carry electrical signals.

Why is the myelin of the peripheral nervous system spared in someone with multiple sclerosis?

In multiple sclerosis (MS), the body’s immune system T cells attack the myelin sheath that protects the nerve fibers. The T cells either partially or completely strip the myelin off the fibers, leaving the nerves unprotected and uninsulated.

How does MS affect the action potential?

In MS, the loss of myelin produces failure of axonal action-potential conduction that is associated with clinical exacerbations, but axonal conduction can recover as a result of expression of new sodium channels along demyelinated axons, providing a substrate for remission of clinical deficits (5).

How does multiple sclerosis affect myelin?

Multiple sclerosis (MS) is the most common demyelinating disease of the central nervous system. In this disorder, your immune system attacks the myelin sheath or the cells that produce and maintain it. This causes inflammation and injury to the sheath and ultimately to the nerve fibers that it surrounds.

Why does destruction of myelin sheath affect motor control?

If the myelin sheath surrounding nerve fibres is damaged or destroyed, transmission of nerve impulses is slowed or blocked. The impulse now has to flow continuously along the whole nerve fibre – a process that is much slower than jumping from node to node.

Does MS affect the peripheral nervous system?

Although it is generally regarded as a disease restricted to the CNS, several studies have reported that some patients with MS also have demyelination in the peripheral nervous system (PNS),4,,8 where axonal fiber demyelination is correlated with a reduced mean myelin sheath thickness and internode length.

What cells are causing the damage in MS?

In the case of MS, the immune system attacks and damages certain structures and cells within the CNS, including: myelin (the fatty sheath that surrounds and protects nerve fibers), oligodendrocytes (myelin producing cells), and. nerve fibers underlying myelin.

What would happen to the nervous system functions if all the neurons were myelinated?

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

Why are some neurons myelinated and others not?

The majority of the neurons in the central nervous system and peripheral nervous system have myelinated axons. This is because the most central nervous system and peripheral nervous system neurons require fast signal transmission such as neurons responsible for spinal reflexes.

How does myelination affect the brain?

Myelination allows more rapid transmission of neural information along neural fibers and is particularly critical in a cerebral nervous system dependent on several long axon connections between hemispheres, lobes, and cortical and subcortical structures.

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 help speed up an action potential?

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 does an action potential not get smaller as it propagates?

An action potential does not get smaller as it propagates along an axon. Why not? Conduction of action potentials is faster in myelinated axons because myelin allows the axon membrane between myelin sheath gaps to change its voltage rapidly, and allows current to flow only at the widely spaced gaps.