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Reflex Action

        Any sudden action in response to some happening in the environment, is called as reflex reaction. The general idea is that we react we react to such a situation without thinking about it or without feeling in control of our reaction. Yet these actions of ours are in response to the stimulus from our surrounding. At this juncture we are forced to think : how is control and co-ordination achieved in such a situation?

        Let us try and understand this in further detail by considering the following example. Touching a vessel containing very hot tea is a dangerous situation for us. How would we respond to a situation like this? one possible way is that we think consciously about the pain and the possibility of getting wounded, and hence we withdraw our hand. Now how long will it take for us to think and perform the activity? If the messages (impulses) have to be sent about the way we have discuss it earlier in the chapter, then it would take quite some time for us to react in response to the situation. But the response to such situations are quick and immediate.
Rather than having to think about the sensation of pain, if the nerves that detect pain were to be connected to the nerves that bring about the movement of the muscle, the action might be completed quickly. Nerves from all over from the body meeting in a bundle in such a connection is commonly called as the spinal cord. Hence reflex arcs are formed in the spinal cord, although the messages reach the brain.

       Reflex arcs are perhaps evolved in animals because the thinking process of the brain is a bit slow. In many animals, specially lower animals the complex neuron network needed for thinking is not there or is not well developed. Hence reflex arcs have been evolved as efficient ways of functioning in the absence of the true through processes. However, in spite of the presence of complex neuron networks, reflex arcs continue to be more efficient for quick responses.