The Sensory Organs and their Function

• The skin, nose, tongue, ears and eyes are our sensory organs.
• They enable us to use our senses of touch, smell, taste, hearing and sight to detect changes in our environment.
• Our senses are our abilities to detect changes in our environment.
• The changes in our environments are called stimuli (singular: stimulus).
• Table below shows the connection between the five senses, the sensory organs and the stimuli.

Sensory Organs	Senses	Stimuli
Skin	Touch	Pain, Cold, cheat, Pressure
Nose	Smell	Chemicals
Tongue	Taste	Chemicals
Ear	Hearing	Sound
Eye	Sight	Light

• When a stimulus is detected by our sensory organs, a message is sent to the brain trough our nerves.
• The brain is the centre of control of our response.
• The brain interprets the message and tells our body how to respond to the stimulus.

Pathway from stimulus to response can be simplified as follow:

• The nerves that carry messages from the sensory organs to the brain are called sensory nerves.
•  The nerves that carry messages from the brain to the muscles are called motor nerves.
• Example: