Multiple Sclerosis Overview
Multiple sclerosis (MS) can be thought of as an immune-mediated inflammatory process involving different areas of the central nervous system (CNS) at various points in time. As the name suggests, multiple sclerosis affects many areas of the CNS.
- Multiple sclerosis is more common in individuals of northern European descent.
- Women are more than twice as likely to develop multiple sclerosis as men.
- Multiple sclerosis usually affects people between the ages of 20 and 50 years, and the average age of onset is approximately 34 years.
Multiple Sclerosis Causes
The central nervous system is made up of the brain and spinal cord. They process information from our environment and control voluntary muscle movements to allow the body to do certain things.
- When you touch something hot, for example, signals are sent from sensory nerve endings in your hand up long nerves in your arm, eventually reaching the spinal cord.
- From there, the signal is transferred up your spinal cord to your brain, where the information is processed. Your brain then sends a signal back down the spinal cord to the nerves in your arm.
- These nerves cause the muscles in your arm to contract, pulling your hand away from the heat.
This neural system works efficiently, unless there is a disease process affecting the pathways in the spinal cord and brain. Multiple sclerosis is one of the diseases that can affect these pathways.
- Signals are transmitted within the central nervous system along pathways.
- These pathways are made up of long fibers called nerves.
- Nerves are capable of transmitting information from the environment to the brain.
- Everything you see, touch, taste, smell, or feel is transmitted along nerves to your brain.
- Nerves also carry information responsible for our alertness, behavior, ability to understand and think rationally, capacity to communicate with others, and feeling and interpreting emotions.
- To help transmit all this information in a timely manner, the nerves are covered by a fatty substance called myelin. Myelin insulates the nerves and allows them to transmit information to and from the brain in a fraction of a second.
- If the myelin is disrupted in any way, the transmitted information is not only delayed, but it may also be misinterpreted by the brain.
Multiple sclerosis results in destruction of the myelin surrounding the nerves of the CNS. The destruction is caused by the body's immune system attacking the myelin sheath. The reason that the body's immune system attacks the myelin sheath is not understood fully, but it is believed to be related to a combination of a genetic predisposition and acquired or environmental influences.
- This autoimmune destruction of the myelin sheath leads to areas of demyelination (also known as plaques) in the brain and spinal cord.
- These plaques disrupt the transmission of information in the CNS and lead to the symptoms seen in multiple sclerosis.
Medically Reviewed by a Doctor on 3/12/2015
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