| A | B |
|---|
| Stimulus | External input to nervous system |
| sensory receptor | cells which pick up the stimulus and turn it into and electrical impulse |
| sensory neurone | runs from receptor to the spine |
| synapse | Gap between the neurones |
| spinal cord | part of CNS in babck of vertebrates |
| motor neurone | runs from end of relay neurone to the effector |
| relay neurone | neuron in spinal cord which joins the sensory neurone to the motor neurone |
| effector | causes effect - muscle of gland |
| muscle | contracts when an impulse hits it |
| gland | secretes a chemical when stimulated by a nerve impulse |
| impulse | electrical signal which flows though the neurones |
| Reflex actions | Automic fast reaction to keep us safe - doesn't go through brain, it is very fast |
