Question

Select the correct statement with respect to disorders of muscles in humans.

• A. An overdose of vitamin D causes osteoporosis.
• B. Accumulation of urea and creatine in the joints causes their inflammation.
• C. Failure of neuromuscular transmission in myasthenia gravis can prevent normal swallowing.
• D. Rapid contractions of skeletal muscles cause muscle dystrophy.

Answer 1

The correct option is C Failure of neuromuscular transmission in myasthenia gravis can prevent normal swallowing.

• Myasthenia gravis is an autoimmune disorder in which autoantibodies bind to acetylcholine receptors on muscle cells and impairs the ability of the neurotransmitter acetylcholine to induce muscular contraction. This leads to fatigue, weakening and paralysis of skeletal muscles of mouth and throat which may prevent normal swallowing.
• Gouty arthritis is caused either due to excessive formation of uric acid or inability to excrete it. It gets deposited in synovial joints and causes inflammation.
• Osteoporosis is a disease in which bone loses minerals and fibres from its matrix. Major causative factors of osteoporosis are imbalances of hormones like calcitonin of thyroid, parathormone of parathyroids, sex hormones and deficiencies of calcium and vitamin D.
• Muscular dystrophy is an inborn abnormality ( mutation of dystrophin gene) of muscles associated with dysfunction and ultimately with deterioration due to breakdown of dystrophin protein.