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Nervous System

Eyes- Light, Ears-Sound, Nose-Chemical, Tongue-Taste, Skin-Touch, Pain, Temperature and pressure.Eyes is a sense organ it contains light receptors. Stimuli change in environment.CNS=Central nervous system- sense organs identify stimuli and use neurone to send electrical impulse through spinal cord to brain and back to effector.                                                                                      Sensory neuron- neurones carry signals from receptors to the spinal cord and brain.   

Relay neuron- carries signals from sensory to Motor neuron.                                              

Motor neuron- nerve cells carry signals from CNS to effector. 

Reflex arc are automatic response to certain stimuli. Eyes pupils become smaller to light to prevent injury and if you get shocked your body releases adrenaline.

Synapse connect neurons- Signals cross this gap using chemicals. One neurone releases the chemical into the gap. The chemical diffuses across the gap and makes the next neurone transmit an electrical signal. Stimuli-Receptor-Sensory-Relay-Motor- Effector-Response.