nervous system

• Stimuli

  Changes that can be detected by the body
• Receptor

  Cells that detect change
• Reflex arc

  Pathway of neurones leading to a rapid automatic response
• Effectors

  Muscles or glands that carry out the response
• Response

  How the body reacts to a stimulus
• Order of the reflex arc

  1. Stimulus
  2. Receptor
  3. Sensory neurone
  4. Relay neurone
  5. Motor neurone
  6. Effector
  7. Response
• Central Nervous System

  1. Brain
  2. Spine
• Functions of reflex action

  1. Rapid
  2. Automatic
  3. Protective
• Where is the Myelin sheath found

  Motor neurone
• What is a myelin sheath

  Fatty substance produced by schwaan cells
• function of the myelin sheath

  Acts as an electrical insulator allowing impulses to transmit quickly and efficiently
• Dendrites

  Carry impulses to the cell body
• Axon

  Carry impulses away from the cell body
• Nerve

  Bundle of neurones
• Nerve Net

  Present in simple organisms
• Nerve nets:

  can't detect the source of stimulus

  Limited number of stimuli

  Consists of simple nerve cells

  Impulse travels in more than one direction

  Unmylinated
• Synapse

  Gap between neurones
• action potential order

  1. Resting potential
  2. Depolarisation
  3. Repolaristaion
  4. Hyperpolarisation or refractory period