Sensitivity and Response Revision

Stimulus - things that set off a reaction in the nervous system

Receptor - a specialised nerve cell which is adapted to respond to a stimulus

Co-ordinator - usually the brain which organises the processes within the body

Neurone - Nerve cells

Sensory Neurone - nerve cells which carry signals from receptors to the spinal cord and brain

Synapse - a tiny gap where two neurones meet

CNS - Central Nervous System

Motor Neurones - They carry signals from the CNS to effectors.

Nerve Impulse - an electrical current that travels along dendrites or axons

Response -  the action that happens after a responding neurone is sent to a muscle e.g the jerk of an arm away from a flame.

Effector - any part of the body that produces the response

• There are two groups of light receptor cells - rods and cones. The rods respond to shades of light (black and white), while the cones respond to colours of light - red, blue and green