Relaxation begins when nerve signals quit stimulating the synaptic knob from releasing acetylcholine. Acetylcholine dissociates from its receptor, and no new molecules of acetylcholine are released.
Tropomyosin moves back into position blocking active sites, and no more contractions can occur. Finally, the muscle fibre returns to its resting length.
What causes sarcomere relaxation to begin?
When the nerve is no longer being stimulated, relaxation takes place. The connection between actin and myosin is then broken by calcium being injected back into the sarcoplasmic reticulum. The muscle relaxes when actin and myosin revert to their unbound condition.
To know more about sarcomere, click here- brainly.com/question/6908670
#SPJ1