PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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while one contracts, the other returns to original length
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both muscles contract at the same time
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both muscles relax at the same time
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1 muscle pulls on the bone and the other pulls on the first muscle
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Detailed explanation-1: -When one of them contracts, the bone is pulled in that direction and the other muscle of the pair relaxes. To move the bone in the opposite direction, the relaxed muscle contracts and the first one relaxes. Thus two muscles have to work together to move a bone.
Detailed explanation-2: -When a muscle contracts, the actin is pulled along myosin toward the center of the sarcomere until the actin and myosin filaments are completely overlapped. In other words, for a muscle cell to contract, the sarcomere must shorten. However, thick and thin filaments-the components of sarcomeres-do not shorten.
Detailed explanation-3: -The prime mover is helped by other muscles called synergists. These contract at the same time as the prime mover. They hold the body in position so that the prime mover can work smoothly. These muscles cause the movement to occur.