the central nervous system

• the CNS coordinates the response
• the CNS is a coordination centre - it receives info from the receptors and then coordinates a response, the response is carried out by the effectors
• stimulus -> receptor -> sensory neurone -> CNS -> motor neurone -> effector -> response
• synapses connect neurones
• the connection between neurones is called a synapse
• the nerve signal is transferred by chemicals which diffuse across the gap
• these chemicals then set off a new electrical signal in the next neurone