PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Why are calcium ions necessary for skeletal muscle contraction?
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Calcium ions increase the speed of the action potential transmitted along the sarcolemma.
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Calcium ions cause ATP binding to actin.
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Calcium ions trigger the binding of myosin heads to actin filaments.
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Calcium ions release the inhibition on Z discs.
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Explanation:
Detailed explanation-1: -The skeletal muscle contraction is caused by calcium ions. These calcium ions bind to the protein complex troponin in order to remove the masking of active site on actin. This results in the exposure of the active-binding sites on the actin for myosin.
Detailed explanation-2: -Calcium diffusing in the cytoplasm between myosin and actin filaments of the muscle fibrils causes the filaments to slide into each other, triggering the contraction of the entire muscle fiber.
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