Myelin Sheath

Topics: Nervous system, Neuron, Myelin Pages: 1 (298 words) Published: December 12, 2013
Myelin Sheath
In a neuron, the myelin sheath consists of fat-containing cells that insulate the axon from electrical activity. This can be compared such as the insulation of a house. The main purpose of the insulation is to increase the rate of transmission of signals in the neuron. There is a small gap between each myelin sheath cell along the axon. Since fat inhibits the proper agitation of electricity, the signals jump from one gap to another. The destruction or loss of the myelin sheath in the central nervous system can cause diseases such as multiple sclerosis. This is also referred to as Demyelination. The symptoms resulted from Demyelination are controlled by the work regularly contributed by the damaged neurons. Some common side effects include visual disturbances, speech, and muscle control. In a myelinated axon the myelin sheath prevents the local current from flowing across the membrane in the neuron. Electrical signals travel faster in axons that are insulated with myelin. Myelin is produced by glial support cells, which wrap around axons and help electrical current flow down the axon. This can compare to such as wrapping duck tape around a leaking water faucet pipe to help water flow down the pipe. Myelin insulation does not cover the entire axon due to breaks in the wrapping. These breaks are called nodes. The distance between these nodes is between 0.2 and 2 mm. Action potentials traveling down the axon "jump" from node to node. This is called saltatory conduction, which means, "to jump”. Saltatory conduction is a faster way to travel down an axon than traveling in an axon without myelin. In other words the main role of the myelin sheath is to speed up nerve cell communications from the brain and spinal cord or to other parts of the body.
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