Z-discs are structural components found in muscle fibers, specifically within the sarcomere, which is the basic unit of muscle contraction. They serve as the boundaries that define each sarcomere, anchoring the thin filaments made of actin. This organization is crucial for the proper functioning of muscles, allowing them to contract efficiently. During muscle contraction, the Z-discs move closer together as the thick filaments, composed of myosin, pull the thin filaments inward. This process is essential for muscle movement and is regulated by the interaction of various proteins, including tropomyosin and troponin, which help control the contraction cycle.