The coordination (also called relation) is one of the main three vital functions. It refers the ability of one living being to be aware of the events happening inside or outside itself and react to them accordingly. It requires:
a) The detection of the stimuli by some receptor, such as the sensory organs (by sensory organs or disperse sensory cells)
b) The transmission of that sensory information to some control centre, (by the afferent nerves)
c) Interpreting that sensory information and generating the response by the mentioned control centre, (by the Central Nervous System)
d) Transmitting the motor information that refers the response, (by the efferent nerves, the endocrine glands and the hormones)
e) Performing the response by some effector, which, in the human body, is a muscle or a gland (by the muscles and the glands).