NEET Biology: Disorders of muscular and skeletal system-Muscular dystrophy Practice Questions
14 free multiple-choice questions on Disorders of muscular and skeletal system-Muscular dystrophy (Locomotion and Movement) for NEET Biology, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. The primary defect underlying most muscular dystrophies is a mutation in which type of gene?
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Correct answer: A — Dystrophin gene
Most muscular dystrophies (like DMD and BMD) are caused by mutations in the gene that codes for the dystrophin protein, which is essential for muscle membrane stability.
Q2. The progressive wasting of skeletal muscle fibers observed in muscular dystrophies is primarily due to the death or degeneration of which muscle cells?
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Correct answer: A — Muscle fibers
Muscular dystrophies involve the degeneration and necrosis of the muscle fibers themselves, leading to muscle weakness and atrophy.
Q3. Muscular dystrophies are primarily classified based on the extent of protein integrity loss. Which type typically involves significant loss of the entire dystrophin gene and results in a more severe phenotype?
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Correct answer: B — Duchenne Muscular Dystrophy
Duchenne Muscular Dystrophy (DMD) is characterized by a complete absence or severe deficiency of dystrophin protein, leading to more profound muscle fiber damage and weakness compared to Becker MD.
Q4. In muscular dystrophy, the progressive weakness in the muscles primarily affects which aspect of locomotion?
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Correct answer: A — Postural stability and walking
Weakness in large skeletal muscles, especially the proximal ones, severely impacts the ability to maintain posture, balance, and perform coordinated walking (locomotion).
Q5. Which symptom is commonly observed in patients suffering from muscular dystrophies due to the inability of muscles to sustain normal activity?
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Correct answer: C — Progressive muscle wasting
Muscular dystrophies involve the progressive breakdown and loss of muscle tissue, resulting in muscle wasting (atrophy) as the disease progresses.
Q6. The muscle fibers in muscular dystrophies typically show a pattern of degeneration that is most severe in which region?
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Correct answer: D — Sarcolemma (muscle membrane)
The pathology involves damage to the sarcolemma (muscle membrane) and subsequent breakdown of the muscle fibers themselves, leading to cellular damage and necrosis.
Q7. Which group of muscles is most commonly affected in Duchenne Muscular Dystrophy (DMD)?
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Correct answer: B — Limb muscles (proximal and distal)
DMD primarily affects skeletal muscles, leading to proximal and distal muscle weakness, making the limb muscles the most visibly affected group.
Q8. Muscular dystrophies primarily affect which type of muscle tissue?
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Correct answer: C — Skeletal muscle
Muscular dystrophies are characterized by progressive degeneration of skeletal muscle fibers.
Q9. Which type of muscle fiber is primarily affected in Duchenne Muscular Dystrophy (DMD)?
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Correct answer: C — Type II muscle fibers
DMD primarily affects the skeletal muscle fibers, specifically the Type II (fast-twitch) muscle fibers, leading to progressive muscle wasting and weakness.
Q10. Which term describes the progressive loss of muscle tissue observed as a consequence of muscular dystrophy?
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Correct answer: D — Atrophy
Atrophy is the reduction in the size of the muscle tissue, which is a defining feature of muscular dystrophies.
Q11. Which of the following components is integral to the structural and contractile function of muscle fibers?
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Correct answer: A — Myofibrils
Myofibrils are the contractile elements within the muscle fiber, composed of actin and myosin filaments, which are responsible for the actual shortening and force generation.
Q12. Which of the following clinical manifestations is most directly related to the inability of muscle fibers to contract effectively due to dystrophy?
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Correct answer: D — Fatigue and weakness
Muscular dystrophy results in progressive muscle weakness and fatigue because the muscle fibers cannot generate sufficient force efficiently.
Q13. Which protein is primarily responsible for maintaining the structural integrity of the sarcolemma in healthy muscle fibers?
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Correct answer: D — Dystrophin
Dystrophin is a crucial protein that links the cytoskeleton (actin) to the extracellular matrix via the dystrophin-glycoprotein complex (DGC), thereby stabilizing the muscle cell membrane (sarcolemma).
Q14. Which observation is a common clinical manifestation of muscular dystrophy in early stages?
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Correct answer: D — Generalized muscle weakness and delayed motor milestones
Early stages of muscular dystrophy are typically characterized by generalized muscle weakness, which directly impacts motor development and physical milestones.
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