MODEL PAPER 7 — Science STD 10 — Question

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 human beings, the control and coordination is brought about by both nervous system and endocrine system. 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. For example, when an emergency stimulus is detected by the nervous system, the stimulus is detected by the nervous system , the stimulus is received and analysed by central nervous system that send message to effectors to provide proper response. At the same time, the sympathetic nervous system activates adrenal gland to release adrenaline that prepares body by increasing heart rate, blood pressure,respiration and dilates pupil etc.
Hence, control and coordination in humans (or animals) depend 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.