How a Response is Generated by Effectors (Edexcel International A Level (IAL) Biology): Revision Note

How a Response is Generated by Effectors

• The nervous system enables the body to detect changes in the environment and brings about appropriate responses to ensure its safety

  • Receptor cells detect changes in the environment, or stimuli

  • Nerve impulses travel from the receptor cells along sensory neurones to the central nervous system, or CNS

  • The CNS acts as a coordinating centre for the impulses that arrive from the receptors, determining which part of the body needs to respond and sending out a new set of impulses along motor neurones

  • Motor neurones send impulses to the effectors to bring about a response

    • Effectors may be muscles or glands

• Nerve impulses pass through the nervous system along the following pathway

stimulus $\to$ receptor $\to$ sensory neurone $\to$ CNS $\to$motor neurone $\to$effector

Receptors detect stimuli and impulses are sent through to the nervous system to bring about a response in the effector