Nervous system and hormones

• Nervous System


  • Fast message (at the speed of electricity)
  • Acts for a short time
  • Message sent to one specific place
  • Immediate reaction
• Hormones


  • Slow message (at the speed of blood)
  • Acts for a long time
  • Message sent to all parts of the body
  • Longer term reaction
• Complex living organisms are aware of their surroundings and can respond to changes in their environment
• Animals can also respond to changes inside their bodies - their internal environment
• This awareness and ability to respond is due to the presence of a nervous system and also hormones
• Nervous System


  • Electrical impulse
  • Transported in neurones (nerves)
• Nervous System


  • Fast speed
  • Short duration
• Nervous System


  • Thinking
  • Throwing
  • Catching
  • Moving
• Hormonal System- type of message

  • Chemical messages
  • Hormones (protein)
  • carried in blood
• Hormonal System speed and duration

  • Slow speed
  • Long duration
• Hormonal Systemexamples 


  • Puberty
  • Adrenaline
• Central nervous system (brain and spinal cord)


  • Coordinates responses between receptors and effectors
• We are able to respond to the environment through the nervous and anything we respond to is called a stimulus. Stimuli are detected by receptors.
• Types of receptors/ stimulus / example


  • Eye / light / reading
  • Nose / smell / cooking
  • Ears / sound / music
  • Skin / touch, temp / pin, fire
  • tongue / taste / eating,
• If a receptor is stimulated it may cause a response. Responses are brought about by effectors. An effector can be either a muscle or a gland.

  Receptors and effectors are linked by a coordinator. The coordinator is usually the brain but may also be the spinal cord. Together they arethe central nervous system.

  Nerve cells(neurones) link the receptors and effectors to the coordinator.