Explain the reflex arc

the reflex arc is a protective mechanism for organisms that protects them from immediate danger. Let us use the example of a hand pulling away from a boiling kettle. the Pain receptors in the skin sense the pain and send this as an electrical signal down the sensory neurone the sensory neurone takes the signal towards the spinal chord where it crosses a synapse (this is a gap between 2 neurones) and arrives at the relay neurone the relay neurone, which is located inside the spinal chord, passes the signal across a synapse to the motor neurone the motor neurone passes the signal to the muscle causing it to contract and pull the hand out of the danger of the kettle. the muscle is the effector. it Effects the change. effectors are either muscles or glands. when looking at a reflex arc always first try and find the receptor and the effect and then work out the path between the 2.