Chapter 11 Tools A B Regulation is the control and coordination Recepters specialized structures that are sensitive to changes in the external and internal enviroment Neuron basic unit of structure and function in the nervous system Impluse electrochemical message Stimuluse change in external and internal enviroment Termial Branches the ends of the axons that secrets neurotransmitters Effectors Are muscles or glands in which neurons are attached to synapses junction between adjactent neurons dendrites receives impluses responses reactions of an organism to a stimulus cyton samething as the cell body cell body recieves the dendrites nerve control function of the nerve cells axon the connection of the cells neurontransmitters stimulates the release of chemicals