Match the term and definition Openings in the sarcolemma [Choose ] Myofilament that has attachment sites for [ Choose ) myosin heads Repeating units in a muscle fiber [ Choose ] Organelle that holds calcium ions [ Choose ] Thread-like components of a muscle fiber [Choose ] Cell membrane of muscle fiber [Choose ] Myofialment responsible for forming a cross- bridge during contraction [ Choose ] Calcium Actin Filament Protein the covers myosin binding sites Sarcomere Troponin Myosin filament Connective tissue layer covering an individual Sarcolemma muscle fiber T-Tubules Endomysium Epimysium Cytoplasm in the muscle fiber Myofibrils Muscle Fiber Acetylcholine sarcoplasm Tropomyosin Sarcoplasmic Reticulum MacBook Pro