Final answer:
In muscle, the tails of myosin molecules coil together to form thick filaments, which are central to muscle contraction. The interaction of thick and thin filaments, made up of myosin and actin respectively, along with regulatory proteins tropomyosin and troponin, are essential for muscle function.
Step-by-step explanation:
In muscle, the tails of myosin molecules coil together to form the central region of a thick filament, anchoring near the M line of the sarcomere. Muscle contraction occurs when the thick and thin filaments slide past each other, facilitated by the myosin heads forming cross-bridges with the actin filaments. The primary component of thin filaments is actin, which has binding sites for myosin. Tropomyosin and troponin are also present in thin filaments, where tropomyosin prevents actin-myosin interaction at rest. Upon muscle activation, calcium ions bind to troponin, causing a conformational change that moves tropomyosin and allows myosin to bind to actin, leading to muscle contraction.