HUMAN PHYSIOLOGY
LOCOMOTION AND MOVEMENT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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H zone
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A band
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O zone
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I band
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Detailed explanation-1: -Upon muscle contraction, the A-bands do not change their length, whereas the I-bands and the H-zone shorten. This causes the Z lines to come closer together.
Detailed explanation-2: -During muscle contraction, the I band is reduced in size as the overlap between the thick and thin filaments increases. The Z-lines come together, and so the sarcomere shortens as well.
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: -When (a) a sarcomere (b) contracts, the Z lines move closer together and the I band gets smaller. The A band stays the same width and, at full contraction, the thin filaments overlap. When a sarcomere shortens, some regions shorten whereas others stay the same length.