A reflex action is an automatic and rapid response to a stimulus, which minimises any potential damage to the body.
It is essential for survival of organisms.
Reflex actions are therefore RAP:
Let us use the example of someone touching something very hot.
1) Receptors in the skin detect a stimulus (something hot i.e. change in temperature)
2) The receptors send an electrical signal along the sensory neurone
3) The sensory neurone then sends these electrical impulses to a relay neurone in the spinal cord
4) The relay neurone connects the sensory neurone to a motor neurone
5) The electrical impulses then travel along the motor neurone towards the an effector muscle
6) The effector muscle produces a movement which is rapid, automatic and protective
7) In this case, the effector muscle moves the hand away from the hot object