The Nervous System Tools A B regulation the control and coordination of all life actvities the 3 basic nervous structures are.... receptors, neurons and effectors receptors structures that are sensitive to change neurons nerve cells which are the basic structures and functions of the nervous system effectors muscles or glands that the neurons are attached to impulses electrochemical messages stimulus a change in the environment that initiates an impulse receptors structures that are specialized to detect stimuli dendrites fibers that detect stimuli and generate an impulse toward the cel body, or the cyton cyton contains the nucleus of the neuron axon a fiber that transmits an impulse away from the cyton and towards the terminal branches terminal branches the ends of the axons that secrete neurotransmitters synapse the gap between the terminal branches of 1 neuron and the dendrites of another neuron neurotransmitters chemicals secreted by the terminal branches that aid in the transmission of an impulse across the synapse the parts that inititiate an a nervous reaction are... impulse, stimulus, and receptors