o Sensory Input: sensory neurons transmit information from external stimuli (light, sound, touch, heat, smell, and taste) and internal conditions (blood pressure, blood, CO2 level, and muscle tension, for example). This info is sent to the CNS for processing.
o Integration: In the CNS, interneuron analyze and interpret the sensory input taking into account the immediate context and what happened in the past. The CNS then decides how to respond.
o Motor Output: leaves the CNS via motor neurons to effector cells which can be either muscle cells or endocrine glands, which then do something (move or release hormones, for example)