Nerves

• Specialised cells - carry electrical impulses around the body
• CNS - the brain and spinal cord

  • involved in voluntary actions
• Reflex arc - involved in involuntary actions
• Reflex Arc:

  Synapses - gaps between neurones

  A) Receptor

  B) Sensory neurone

  C) relay neurone

  D) motor neurone

  E) Effector

  F) Synapses

  
• Impulse arrives at a muscle = muscle contracts
• Arrives at a gland = release of hormones
• Receptors in a sense organ detect a stimulus (a change in an external or internal environment)
• An electrical impulse travels along a neuron to the spinal cord and brain
• Impulses travel back from the brain to an effector