Your senses and nervous system
The sense organs contain receptors that are sensitive to stimuli.
Human vision is binocular, which gives us a good perception of depth. Vision defects include short-sightedness, long-sightedness and colour blindness.
The nervous system consists of the central nervous system - brain and spinal cord -and peripheral nerves. Nerve impulses travel through the axons of neurones - nerve cells. Reflex actions are fast, automatic and protective responses.
Receptors are groups of specialised cells. They can detect changes in the environment, which are called stimuli, and turn them into electrical impulses. Receptors are often located in the sense organs, such as the ear, eye and skin. Each organ has receptors sensitive to particular kinds of stimulus.
|sense organs||receptors sensitive to|
|touch, pressure, pain and temperature|
|chemicals in food|
|chemicals in the air|
|sound and position of the head|
The central nervous system - CNS - in humans consists of the brain and spinal cord. When a receptor is stimulated, it sends a signal along the nerve cells - neurones - to the brain. The brain then co-ordinates the response.
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