74. Myasthenia Gravis is primarily caused due to
1. degeneration of muscles.
2. defects in adrenergic receptor system.
3. defects in the cholinergic receptors system.
4. kidney failure.

 

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What is Myasthenia Gravis?

Myasthenia Gravis (MG) is a chronic neuromuscular disorder characterized by weakness in the skeletal muscles, particularly those that control eye movement, facial expression, and swallowing. It occurs due to an impaired communication between the nerves and muscles, leading to muscle weakness and fatigue.

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Primary Cause of Myasthenia Gravis

The primary cause of Myasthenia Gravis is the defect in the cholinergic receptors system, specifically the acetylcholine receptors at the neuromuscular junction. Acetylcholine is a neurotransmitter that is released from nerve endings to stimulate muscle contraction. In Myasthenia Gravis, the body’s immune system produces autoantibodies that block or destroy these acetylcholine receptors, preventing proper muscle contraction and leading to muscle weakness.

Evaluation of the Given Options:

1. Degeneration of muscles – This is incorrect. Myasthenia Gravis is not caused by degeneration of muscles but rather by defective neurotransmission at the neuromuscular junction due to immune system malfunction.

2. Defects in adrenergic receptor system – This is incorrect. The adrenergic receptors are involved in responses to adrenaline and are not primarily responsible for Myasthenia Gravis. The condition is related to the cholinergic system, which involves acetylcholine receptors.

3. Defects in the cholinergic receptor system – Correct. This is the primary cause of Myasthenia Gravis. The disease occurs when antibodies block or destroy acetylcholine receptors, preventing effective communication between nerves and muscles.

4. Kidney failure – This is incorrect. Kidney failure is not related to the cause of Myasthenia Gravis. The disorder is not associated with kidney function but with nerve-muscle communication dysfunction.

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Correct Answer: Option 3

Defects in the cholinergic receptors system is the primary cause of Myasthenia Gravis.

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Conclusion

Myasthenia Gravis is primarily caused by defects in the cholinergic receptor system, where the immune system produces antibodies that attack acetylcholine receptors. This leads to impaired nerve-muscle communication and muscle weakness. Understanding this cause is essential for diagnosing and treating the condition effectively.