Individual fibers can extend the entire length of the muscle. The firm white tendons form a core for the red muscle by extending far inside its mass and emerging at the ends of the muscle to link it to bone. Muscle fibers and tendon fibers are completely different materials and do not merge. Instead, the connective tissue extending from the tendon forms a cuplike receptacle for the muscle fiber endings. Other fibers tangle around the muscle fiber, binding it to the receptacle.
Skeletal muscle is striated.
The striations arise from the many myofibrils , each of which is striated. The parallel arrangement of myofibrils within the muscle cell gives it its characteristic appearance. Just as a single fiber contains many myofibrils, each myofibril contains many smaller filaments arranged in a repeated pattern along the length of the fibril. There are thick filaments composed of the protein myosin and thin filaments composed of the protein actin . The arrangement of the filaments makes the striations.