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The following points highlight the sixteen important diseases of neural system.
Disease # 1. Poliomyelitis:
Poliomyelitis is an acute viral infection that destroys the cell bodies of motor neurons in the anterior horn of the spinal cord.
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Disease # 2. Meningitis:
Meningitis, an inflammation of the meninges, is usually caused by an infectious organism. Several kinds of bacteria and viruses can infect the meninges.
Disease # 3. Neuritis:
More of a symptom than a specific disease, neuritis is a general term for disturbances of the peripheral neural system. Either sensory or motor fibres or both may be damaged.
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Disease # 4. Multiple sclerosis:
Multiple sclerosis is a progressive degenerative disease of central neural system, so named because of the many sites in which hardened (or sclerotic) tissue has replaced the normal myelin sheaths of neurons.
Disease # 5. Sciatica:
It is an irritation or neuritis of the sciatic nerve. In fact it is pain along the sciatic nerve. The most common cause of sciatica is a “slipped” intervertebral disc. A disc in the lumbar area herniates or protrudes from the vertebral column.
The central part of the disc may be pushed out through the peripheral fibrous part, causing pressure to be placed on the sciatic nerve. Other causes of sciatic include osteoarthritis and pregnancy, if the weight and position of foetus creates pressure on the sciatic nerve.
Disease # 6. Neuralgia:
Neuralgia is pain in a circumscribed area innervated by a sensory nerve of the peripheral neural system. It is often impossible to determine the case of the pain and difficult to relieve it.
Disease # 7. Parkinson’s Disease.Cause:
It is caused by the destruction of the neurons of basal ganglia that produce the neurotransmitter dopamine. Thus dopamine is reduced in the brain.
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Symptoms:
Symptoms include tremors and shakes in the limbs, a slowing of voluntary movements and feeling of depression.
Treatment:
It is treated by dopamine. The drug Exelon, prescribed to restore memory in Alzheimer’s patients, may also offer some help for people who develop dementia from Parkinson’s disease. One of the examples of this disease is the great boxer Mohammed Ali.
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Neural System: Disease # 8. Wilson’s Disease:
Along with all symptoms of Parkinson’s disease, there is degeneration of liver tissues also. The degeneration changes in liver and brain are due to disturbed copper metabolism. Wilson’s disease is due to damage of the lenticular nucleus (a part of basal ganglia).
Neural System: Disease # 9. Alzheimer’s Disease (AD):
Causes:
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It is caused due to destruction of vast numbers of neurons in the hippocampus (a part of brain). Evidence suggests that it is due to a combination of genetic factors, environmental or lifestyle factors and the ageing process. There is loss of neurotransmitter acetylcholine.
Symptoms:
Individuals with AD initially have trouble remembering recent events. In the later stages, the patients may fail to recognise their spouse or children. The disease is due to dementia (progressive loss of memory). Treatment. Drugs that inhibits acetyl cholinesterase (AChE), the enzyme that inactivates acetylcholine (ACh), improve alertness.
Tacrine, the first anticholinesterase inhibitor approved for treatment of AD in the United States, has significant side effects. Donepezil, approved in 1998, is less toxic to the liver. Some evidence suggests that vitamin E (an antioxidant), oestrogen and ubuprofen may have beneficial effects in AD patients. Former USA President Ronald Reagan was suffering from Alzeheimer’s disease.
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Neural System: Disease # 10. Schizophrenia Causes:
(i) Genetic factors:
It tends to run in some families.
(ii) Brain dysfunction:
Some findings indicate that some ventricles of the brain are larger in schizophrenics than in other persons and this increased size may produce abnormalities in the cerebral cortex.
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(iii) Biochemical factors:
Drugs that increase dopamine activity in the brain tend to intensify schizophrenic symptoms.
(iv) Psychological factors:
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The patients are more likely to suffer relapses when their families engage in harsh criticism (“you are nothing but trouble”), etc.
Symptoms:
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This disorder is characterized by hallucinations (e.g., seeing things or hearing voices that are not really there), delusions (beliefs with no basis in reality), disturbances in speech, disordered thought processes and disordered behaviours.
Neural System: Disease # 11. Broca’s aphasia:
There is an inability to speak in fluent sentences, although the person has no problem in understanding written or spoken words due to damage to the Broca’s area in the frontal lobe of the cerebrum of the brain.
Neural System: Disease # 12. Wernicke’s aphasia:
There is difficulty in understanding spoken or written words and in putting words into meaningful sentences as a result of injury to the Wernicke’s area in the temporal lobe of the cerebrum of the brain.
Neural System: Disease # 13. Amnesia as a Result of Korsakoff’s Syndrome:
Individuals who consume large amounts of alcohol for many years develop this illness. Symptoms of Korsakoff’s syndrome include sensory and motor problems as well as heart, liver and GIT disorders and also amnersia (loss of memory). It is due to extensive damage to the portions of the thalamus and hypothalamus of the brain.
Neural System: Disease # 14. Myelodysplasia:
It is the abnormality in the development of the spinal cord.
Neural System: Disease # 15. Tabes Dorsalis:
This is a slowly progressive nervous disorder affecting both the motor and sensory functions of the spinal cord.
Neural System: Disease # 16. Syringomyelia:
The presence of fluid filled cavities in the spinal cord is known as syringomyelia.
