1. Reacts to the world around you.
2. 5 sense organs and receptors
   1. Eyes
      1. Light receptors
   2. Ears
      1. Sound Receptors
      2. "Balance" receptors
   3. Nose
      1. Smell receptors
         1. chemical stimuli
   4. Tongue
      1. Taste receptors
         1. chemical stimuli
   5. Skin
      1. touch
      2. pressure
      3. temperature change
3. Stimulus
   1. light
   2. sound
   3. touch
   4. pressure
   5. chemical
   6. position change
   7. temperature change
4. Receptors
   1. convert stimulus to electrical impulse
5. Neuron
   1. nerve cells
   2. transmits
      1. information
      2. electrical impulses
   3. Sensory Neuron
      1. receptors to CNS
   4. Relay Neuron
      1. spinal cord
      2. unconscious part of brain
   5. Motor Neuron
      1. CNS to effectors
   6. synapse
      1. connection between neurons
      2. nerve signal transfer
         1. diffusion of chemicals betweeen gap
6. Central Nervous System
   1. Brain + Spinal Cord
   2. gathers info from sense organs
   3. reflexes and actions coordinated
7. Effectors
   1. muscles
      1. contract
   2. glands
      1. secrete hormones
8. Reflexes
   1. prevent injury
   2. automatic
   3. bright light in eye
      1. pupils smaller
   4. shock
      1. hormone adrenaline
9. REFLEX ARC
   1. stimulus
   2. receptor
   3. sensory neuron
   4. relay neuron
   5. motor neuron
   6. effector
   7. response
10. Hormones
    1. DEFINITION
       1. chemical messengers which travel in the blood to activate target cells
    2. chemical messengers
       1. released into blood
          1. blood plasma
          2. travel at speed of blood
    3. affect particular cells
       1. target cells
    4. help control organs & cells
       1. needing constant adjustment
          1. not life immediately threatening
    5. produced in glands
    6. long lasting effects
    7. GLANDS
       1. pituitary gland
          1. FSH
             1. Follicle Stimulating Hormone
          2. LH
             1. Luteinising Hormone
          3. ADH
             1. controls water content
       2. Pancreas
          1. insulin
             1. blood sugar
       3. Ovaries
          1. oestrogen
             1. controls mentrual cycle
             2. female secondary characteristics
             3. extra body hair
             4. widening hips
          2. female only
       4. Testes
          1. male only
          2. testosterone
             1. male secondary characteristics
             2. extra hair
             3. changes in body proportions
    8. The endocrine system controls the way your body functions. It produces hormones that travel to all parts of your body to maintain your tissues and organs
11. Hormone / nerve comparison
    1. Nerves
       1. very fast
       2. act for short time
       3. act veru precise area
       4. electrical message
    2. Hormones
       1. slower
       2. act long time
       3. act general
       4. chemical message