RESPONDING TO THE ENVIRONMENT

• Receptors = detect stimuli. They can be cells or proteins
• Effectors = bring about a response to a stimulus. They can be muscle cells and cells found in glands
• Sensory neurones = transmit electrical impulses from receptors to the CNS
• Motor neurones = transmit electrical inpulses from the CNS to effectors
• Relay neurones = transmit electrical impulses between sensory and motor neurones

stimulus --> receptors --> CNS --> effectors --> response

Nervous communication:

• Localised - neurotransmitters are secreted directly onto cells
• Short-lived - neurotransmitters are quickly broken down
• Rapid - electrical impulses are fast