Answer:
Muscle contraction can be explained by sliding filament theory.
1. Activation of muscles: the motor nerve generates an impulse to transfer signals from neurons to neuromuscular junction. This stimulates sarcoplasmic reticulum to release calcium into the muscle cells.
2.Contraction of muscles: calcium in the muscle cells binds with troponin causes actin and myosin to bind. Actin and myosin in the muscle binds and contract by utilizing ATP as a source of energy.