HUMAN PHYSIOLOGY
LOCOMOTION AND MOVEMENT
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Actin (thin filament) moves past myosin (thick filament)
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Myosin moves past actin
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Both myosin and actin move past each other
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None of these is correct
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Detailed explanation-1: -According to the sliding filament theory, the myosin (thick filaments) of muscle fibers slide past the actin (thin filaments) during muscle contraction, while the two groups of filaments remain at relatively constant length.
Detailed explanation-2: -Sliding Filament Theory According to this theory, myosin filaments use energy from ATP to “walk” along the actin filaments with their cross bridges. This pulls the actin filaments closer together.
Detailed explanation-3: -During contraction, the myosin heads extend from the thick filament surface and attach to actin in the thin filaments, causing the filaments to slide past each other in a cyclic, ATP-driven process.
Detailed explanation-4: -Sliding-filament model of muscle contraction. The actin filaments slide past the myosin filaments toward the middle of the sarcomere. The result is shortening of the sarcomere without any change in filament length.
Detailed explanation-5: -Correct answer: In the sliding filament theory, myosin heads attach to an actin filament, bend to pull the actin filaments closer together, then release, reattach, and pull again.