Paralysis is the loss of the power to move a part of the body due to injury or disease of the nerves that supply the muscles involved in moving that part of the body. The key points in this definition are firstly that paralysis refers to a loss of movement rather than just weakness, and secondly that the problem originates in the nerves to the muscles rather than in the muscles themselves. The severity of the paralysis is indicated in medical terminology by the word endings: plegia and paresis. Plegia signifies loss of power, i.e. true paralysis; while paresis refers to a significant weakening of the affected muscle(s). The part or parts of the body which are paralysed (-plegic) or very weak (-paretic) are identified in medical terms by the part of the word that comes in front of the ‘-plegia’ or ‘-paresis.’ Another term occasionally used, but meaning the same as paralysis, is palsy. Damage to the nerves supplying the muscles of the face is described as facial palsy. Cerebral palsy is paralysis that is the result of damage to the brain (or cerebrum). Causes
Paralysis is most often caused by damage to the nervous system, especially the spinal cord. Major causes are stroke, trauma, poliomyelitis, amyotrophic lateral sclerosis (ALS), botulism, spina bifida, multiple sclerosis, and Guillain-Barré syndrome. Temporary paralysis occurs during REM sleep, and dysregulation of this system can lead to episodes of waking paralysis. Drugs that interfere with nerve function, such as curare, can also cause paralysis. Many causes of this are varied, and could also be unknown. Paralysis is caused by something being wrong with the nerves that activate muscles. Another word for nerve is neurone. The nerves that send the electrical messages, or impulses, to muscles to make them move or contract are called motor neurones. When we move a part of our body two types of motor neurone are involved in getting the relevant muscles to move: the...
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