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Sarkari MCQs Government Exam Question Bank
Question no. 63554

What occurs physiologically in myasthenia gravis_______________?

Select your answer for: What occurs physiologically in myasthenia gravis_______________?
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Answer: B. Lack of acetyl choline receptors

Explanation

Myasthenia gravis is an autoimmune disease destroying acetylcholine receptors at the junction. Antibodies target postsynaptic receptors, reducing the number available for binding. Option B is correct because the disorder features a lack of acetylcholine receptors. Neuromuscular transmission relies on acetylcholine binding to postsynaptic nicotinic receptors. Receptor destruction impairs muscle depolarization and causes profound physical fatigue. Clinical symptoms include fluctuating muscle weakness that worsens with repetitive activity.

Acetylcholinesterase inhibitors help increase synaptic neurotransmitter availability to improve strength. Thymectomy is often performed because the thymus gland plays a role in disease pathogenesis. Respiratory muscle weakness during myasthenic crises requires emergency mechanical ventilation. Acetylcholine synthesis remains normal, but postsynaptic receptors are destroyed by antibodies. Isometric contraction is a normal physiological muscle action rather than a disease cause. Muscles become weak and fatigued rather than rigid and tough in myasthenia gravis.

Subject
Medical
Category
Medical
Topic
—
Difficulty
medium

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