These groups include both sensory fibers and motor fibers. Groups A and B are myelinated, and group C are unmyelinated. Nerve fibers are classed into three types – group A nerve fibers, group B nerve fibers, and group C nerve fibers. Axon dysfunction can be the cause of many inherited and acquired neurological disorders that affect both the peripheral and central neurons. In certain sensory neurons ( pseudounipolar neurons), such as those for touch and warmth, the axons are called afferent nerve fibers and the electrical impulse travels along these from the periphery to the cell body and from the cell body to the spinal cord along another branch of the same axon. ![]() The function of the axon is to transmit information to different neurons, muscles, and glands. Some research is investigating drugs that promote myelin repair, which would mean that damage could be reversed and function improved.An axon (from Greek ἄξων áxōn, axis), or nerve fiber (or nerve fibre: see spelling differences), is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body. Some research is looking into drugs that protect nerves from damage and so halt or slow down the progression of MS. Remyelination and neuroprotection are potential areas where new treatments could be developed. Messages to or from that part of the central nervous system are permanently blocked, resulting in symptoms that do not improve for you. Should the area of damage become too large, this rerouting process is no longer able to compensate. Messages may take longer to get through but your symptoms will improve to some extent. This ability to adapt to avoid damaged areas is called plasticity. Your central nervous system is able to overcome small areas of nerve damage by rerouting messages using undamaged nerve cells. If an axon is left without the protection of myelin it will be more vulnerable to damage and may die. Eventually, they may not be able to produce more myelin. Remyelination tends to occur in the earlier stages of MS but, with repeated relapses or attacks, oligodendrocytes become damaged and destroyed. Although the new myelin can work effectively, it tends to be thinner than unaffected myelin and so messages through the affected nerves may not be as fast as before the attack. Once the inflammation caused by the immune attack is over, it is possible for the body to replace damaged myelin. They include oligodendrocytes which produce myelin. Nerve cells are surrounded by support cells called glial cells. The thickness of the myelin sheath and the size of the gap between nodes determine the speed of messages, which can be as fast as 120 metres/second (268mph). ![]() Nerve messages leap along the axon from node to node. The myelin sheath has short gaps about one micrometre apart known as Nodes of Ranvier. Myelin acts as insulation to the axon and prevents messages becoming interrupted. The axon is surrounded by a sheath of fatty protein called myelin. They are collected by receptors on the dendrites of neighbouring neurons, and the message continues on its way. To cross the synapse, neurotransmitters are released at the end of the neuron. The synapse is the space between an axon and a dendrite of another neuron. ![]() Information enters the neuron via the dendrites, passes through the cell body and then along the axon until it reaches the synapse. The axon can be as long as one metre, making neurons some of the longest cells in the body. A neuron usually has a number of dendrites but only one axon, although this axon may have extensive branching. Neurons have specialised extensions called dendrites and axons. ![]() Pharmaceutical and other industry supporters.
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