What is the role of calcium in muscle contraction?

Role of calcium in muscle contraction:

1. During muscle contraction, microfilaments move over thick filaments.
2. A transmitter sent out by the nervous system via a motor neuron causes muscle movement.
3. Chemicals called neurotransmitters are released when a neural signal is applied to a neuromuscular junction and an excitatory is formed in the sarcolemma.
4. Like the signal travels through the muscle fiber, calcium ions are released in the sarcoplasm. Calcium then activates myosin by shackling to troponin on the cytoskeleton.