Describe the coordination of a reflex action.

the receptor detects stimulus. The receptor generates an electrical impulse sent to the CNS by neurons (sensory). Chemical messengers (neurotransmitters) carry the electrical impulse across a synapse. Neurotransmitter stimulates impulse(s) in the next neuron. The relay neuron is reached. The motor neuron sends a message to the effector which carries out response (muscles contract or gland secretes chemicals).