Overlapping of thick and thin filaments occurs in:
Correct answer: B. A band
- A. I band
- B. A band
- C. M band
- D. Z band
Explanation
The myosin and actin filaments overlap in peripheral regions of the A band, whereas a middle region (called the H zone) contains only myosin. The I-band is the region on either side of a Z-disc that contains only thin filaments and titin.
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About Muscle Contraction
Muscle contraction is explained by the sliding filament model, in which myosin heads pull actin filaments within sarcomeres using ATP. The topic covers calcium, troponin, tropomyosin, the neuromuscular junction and relaxation, with attention to how filament length stays almost constant while the sarcomere shortens.
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