The main receptors :
Eyes - sensitive to light
Ears - sensitive to sound and change in position
Nose and tongue - sensitive to chemicals
skin - sensitive to pain, pressure, heat and tempreture
The main job of the Central Nervous System (CNS) is to keep movements co-ordinated and allow you to react to your surroundings.
Hormones are chemical messengers/substances
Effector organs = muscles or glands
Special glands make hormones and release them into your body
Stimuli = light, scent, noise E.C.T.