PHYSIOLOGY
MUSCLE CONTRACTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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actin head attaching to myosin binding site
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ligaments and tendons
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bones and muscles
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none of these
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Detailed explanation-1: -The cross-bridge formed from the binding of actin with myosin. The formation shows muscle shortening caused by the movement of the contractile protein. The cross-bridge muscular contraction cycle is identified in all muscle types, including cardiac, smooth, and skeletal muscles.
Detailed explanation-2: -noun. cross·bridge ˈkrȯs-ˌbrij. : the globular head of a myosin molecule that projects from a myosin filament in muscle and in the sliding filament hypothesis of muscle contraction is held to attach temporarily to an adjacent actin filament and draw it into the A band of a sarcomere between the myosin filaments.
Detailed explanation-3: -The muscle contraction cycle is triggered by calcium ions binding to the protein complex troponin, exposing the active-binding sites on the actin. As soon as the actin-binding sites are uncovered, the high-energy myosin head bridges the gap, forming a cross-bridge.