6.6 STRUCTURE OF THE HUMAN GAS-EXCHANGE SYSTEM

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  • 6.6 Structure of the human GE system
    • Aerobic org req const supply O to release NRG (ATP) during resp
      • CO2 prod in resp proc need removed as build-up = harmful
    • Mammalian lungs
      • Lungs inside body bc air not dense enough to sup + body would dry out (lose water)
      • Ribcage supports + protects
      • Lungs -  lobed struc - series highly branched tubules (bronchioles) - end in tiny air sacs (alveoli)
        • alveoli - minute air sacs - end bronchioles - btwn r collagen + elastic fibres. + lined w epithelium. elastic fibres allow alveoli 2 strechas fill during breathing in, spring back during breathing out to expel CO2.
          • Alveolar membrane = GE S
      • Trachea - flexible airway. Sup by ring cartilage - prevent collapsing as air pressure inside falls (breathing in). Tracheal walls made of muscle, lined w epithelium & goblet cells.
      • Bronchi - 2 divisions trachea, each leading to other lung. Sim in struc t trachea. They also prod mucus - trap dirt particles + cilia moves dirt-laden mucus towards throat.
  • maintain high body temp which related high metabolic + respiratory rates
    • So, mammals evolved specialised exch surf: lungs
      • relatively large org w/ large vol living cells
    • Volume O that has to be abs and vol CO2 removed large in animals bc
      • relatively large org w/ large vol living cells
      • CO2 prod in resp proc need removed as build-up = harmful

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