The working together of various organs of human being in a systematic, controlled and efficient way to produce a proper response to various stimuli is known as coordination. In humans, the nervous and hormonal system together perform this control and coordination. Nervous system consists of receptors that receive the stimulus from surrounding environment and send the message received by them to the spinal Cord and brain in form of electrical impulses through the sensory nerves. The motor nerves then transmit the response to the effector. The effectors are mainly the muscles and glands of our body. Thus, endocrine glands secreting hormones are directly or indirectly controlled by the nervous system. Hence, control and coordination in humans (or animals) depends on two things for transmitting information, i.e. chemical signals of hormones and nerve impulses.
If they depended only on nerve impulses through nerve cells, only a limited range of tissues would be stimulated. Since, they get additional chemical signals as well, a large number of tissues are stimulated. This is why animals can show a wide range of response to stimulus.