PHYSIOLOGY
SLIDING FILAMENT MODEL
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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True
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False
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Either A or B
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None of the above
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Detailed explanation-1: -During muscle contraction, each sarcomere shortens, bringing the Z discs closer together. There is no change in the width of the A band, but both the I bands and the H zone almost completely disappear.
Detailed explanation-2: -The primary function of the Z-band is the transmission of tension from one sarcomere to the next. As actin filaments are not continuous through the Z-band, the tension has to be transmitted through the Z-band assembly; hence, understanding the 3D structure is important.
Detailed explanation-3: -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.
Detailed explanation-4: -So, the correct answer is ‘A-Band remains constant’.