''Reflex arcs continue to be more …

Reflex arc is the pathway followed by reflex action. Reflex action is an automatic, rapid and immediate reaction to a stimulus and is below the level of consciousness. No thinking is involved in reflex action. For example - When we unknowingly touch a hot plate or pan, we pull away our hand very quickly and without thinking. The stimulus here is the heat which we feel in our hand. This heat is sensed by a heat receptor which triggers an impulse in a sensory neuron and transmits message to spinal cord. The impulse is passed on to a relay neuron, which in turn, passes it to a motor neuron. The motor neuron passes the impulse to a muscle of the arm which then contracts and pulls our hand away from hot plate or pan. The muscle of arm is an effector because it responds to the stimulus. Hence, reflex arcs continue to be more efficient for a quick responses.