Neurotransmittors These chemicals qualify as hormones according to the definition of a hormone, but their special action in the nervous system sets them apart. A comparison Nervous Communication Endocrine Communication Response to a stimulus, internal or external. Response to a stimulus, internal or external. Impulse travels electrochemically along axons and chemically across synapses as neurotransmitter. Message generally travels chemically as hormones in the circulation.
Response is specific in target neurone, muscle or gland.
Response is often widespread in several target tissues in the body Response is generally short-lived. Response is generally long-lasting in regulating metabolism Initiates short acting chemical changes in target tissue. Influences specific chemical changes and regulates metabolism, growth or reproduction. The ability to control body temperature is extremely important if animals are to survive. Recall from Area of Study 1 that enzymes have optimal temperatures for their activity.