The sarcomere is the basic functional unit of muscle• The thick filament consists of a few hundred myosin molecules arranged in a structured sequence.• The primary components of the thin filament are two helical strands of fibrous F-actin, each of which• contains approximately 200 actin monomers.• Superimposed on F-actin are tropomyosin and troponin, proteins that control the interaction between actin and myosin• Tropomyosin consists of two coiled strands that lie in the groove of the F-actin helix; • troponin is a small molecular complex that is attached to tropomyosin at regular intervals