How do the structures (myofibrils, actin, and myosin) in muscle fibers facilitate muscle contraction?
Answer 1
Elizabeth Smith
Muscle contraction is facilitated by the interaction of myofibrils, actin, and myosin within muscle fibers. Myofibrils are composed of repeating units called sarcomeres, which contain actin (thin filaments) and myosin (thick filaments). During contraction, myosin heads bind to actin filaments, forming cross-bridges. Through ATP hydrolysis, myosin heads pivot, pulling actin filaments towards the sarcomere center, resulting in muscle shortening and contraction.
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