nervous system

• what does CNS stand for?

  central nervous system
• nerve fibres

  • are nerves that are grouped together
  • are a mix of sensory & motor nerves
• impulses can travel through nerves at 100 metres per second
• sensory nerves take information from the body to the brain
• motor neurons take information to the muscles
• reflex actions

  • you have no control over them
  • sends messages to the spinal cord & not the brain
• order of nervous system

  1. sensory neurone
  2. relay neurone
  3. motor neurone
  4. effector
• afferent neurons

  • input information & carry it from different parts of the body to the brain
• efferent neurons

  • outputs information from the brain back to the body
• order of reflex action

  • afferent neuron = sensation
  • CNS = decision
  • efferent neuron = reaction
• ears sense

  • sounds & balance
• eyes sense light
• skin senses temperature, touch & pain
• nose senses chemicals