When the sarcomere contracts and shortens,D) the A band stays the same.
When a sarcomere contracts, the Z strains flow nearer together and the I band receives smaller. The A band remains equal width and, at full contraction, the skinny filaments overlap. Whilst a sarcomere shortens, some areas shorten while others live the equal length.
At some stage in muscular contraction, the myosin heads pull the actin filaments closer to one another ensuing in a shortened sarcomere. while the I band and H sector will disappear or shorten, the A band length will continue to be unchanged.
A sarcomere is described as a distance between the Z-strains. The Z-strains are pulled closer together for the duration of contraction and move in addition apart in the course of relaxation. The Z-traces are closer for the duration of contraction because actin and myosin interplay generates pass-bridges, which slide the myofilaments over every other.
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