PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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I band
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A band
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Z line
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H zone
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M line
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Detailed explanation-1: -During muscle contraction, the I band reduces in size as the overlap between the thick filaments and the thin filaments increases. The H zone also decreases in length because of the same reason.
Detailed explanation-2: -The H zone-the central region of the A zone-contains only thick filaments and is shortened during contraction.
Detailed explanation-3: -When muscle contracts, the H zone (central region of Azone) which consists of thick filaments is shortened and the I band which contains only thin filaments is also shortened during the time of contraction.
Detailed explanation-4: -The H zone-the central region of the A zone-contains only thick filaments (myosin) and is shortened during contraction. The H zone becomes smaller and smaller due to the increasing overlap of actin and myosin filaments, and the muscle shortens.
Detailed explanation-5: -So, the correct answer is ‘Decrease in length of actin myofilaments’.