5. NERVOUS SYSTEMS

• What is the nervous system made up of?

  Made up of neurones (nerve cells) which go through to all parts of the body
• What are receptors?


  A group of cells that can detect a change in your environment (a stimulus)
• Different receptors detec different...


  stimuli
• What happens when a stimuli is detected by receptors?


  The information is converted to a nervous (electrical) impulse, and sent along sensory neurons to the CNS.
• The CNS coordinates...


  the response
• What does the CNS decide?

  It decides what to do about the stimulus and tells something to do it. The impulses travels through the CNS along relay neurones.
• CNS sends information to an effector along...


  motor neurone. the effector then responses accordingly.
• Process.

  A) stimulus

  B) receptor

  C) sensory neurone

  D) motor neurone

  E) effector

  F) response

  
• What is a reaction time?

  Time it takes for you to respond to a stimulus
• What is a dendrite?

  It carries nerve impulses towards the cell body
• What is an axon?

  It carries nerve impulses away from the cell body
• What is a myelin sheath?


  It acts as an electrical insulator, speeding up the electrical impulse
• What do all neurons have?

  A cell body with a nucleus and cytoplasm and other subcellular structures
• What do cell bodies have?


  Dendrites which are extensions that connects other neurons, and dendrons carry nerve impulses toward the cell body and axons carry nerve impulses away from the cell body
• What are some axons surrounded by?


  Myelin sheath
• Why is one long neurone much quicker than lots of short ones joined together?

  Connecting with another neurone slows the impulse down