Communication Systems

Communication Systems

1. External Environment

   • Can be air, water or soil. It can change and put the organism under stress
     • Slow changes e.g. Season change/global warming
     • Fast change e.g. Day to night/sunshine to darkness

2. Detecting changes

   • High blood sugar levels after a meal
     • Body releases insulin - hormonal
   • Smelling delicious food
     • Mouth waters - nervous
   • Torch shone in eye
     • Pupils contract - nervous
   • Sudden drop in external temperature
     • Shiver - nervous

3. Internal Environment

   • Cells...
     • ...do metabolic reactions, use up substrates and produce products e.g. CO2
       • CO2 needs excreting
         • This means the removal of waste to prevent accumulation in the blood
           • CO2 needs excreting as it can build up in tissue fluid ad disrupt enzyme action of cells, and change pH levels
     • ...are bathed in tissue fluid which is made from the blood