How Does Muscle Contraction Occur at the Cellular Level?
Muscle contraction involves the sliding filament mechanism, where actin and myosin filaments slide past each other to shorten the muscle fiber. The process is initiated by a nerve impulse that triggers the release of calcium ions from the sarcoplasmic reticulum. Calcium ions bind to troponin, causing a conformational change that moves tropomyosin away from the myosin-binding sites on actin filaments, allowing cross-bridge formation.
