The muscles of the body are part of the musculoskeletal system but would not operate without the system providing the impulses that cause the muscles to act.

The answer is nervous system.

Neurones are part of the nervous system. Impulses from the brain in the form of action potential travel from brain centres through the neurones. A contact between a neurone and a muscle fibre is called a neuromuscular junction. When an action potential reaches the end (presynaptic terminal) of a motor neurone, it will induce a release of neurotransmitters from the motor neurone. Neurotransmitters pass through the synaptic cleft and bind to the receptor on the muscle fibre which results in muscle contraction.

It would be 232.4242