The respiratory system

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  • Created by: Nadia
  • Created on: 02-01-13 18:29
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  • Respiratory System
    • most animals need a specialised respiratory system to absorb oxygen from their blood and get rid of waste carbon dioxide from their blood to the air
    • respiratory system consists of the nasal cavity, trachea, bronchi, bronchioles, alveoli, lungs, diaphragm, ribs + intercostal muscles
    • breathing in happens when the ribs move up + out, the diaphragm moves down
      • this increases the volume of the thorax
      • when exhaling, these changes are reversed
    • respiratory surfaces need to be thin _ moist, have a large surface area +a good blood supply
    • gas exchange in mammals take place by diffusion into the alveoli
    • inspired air has more oxygen, less carbon dioxide and less water vapour than expired air
      • the air we exhale is warmer than the air we inhale
    • dust and other unwanted/ foreign particles are prevented from entering the lungs by mucus
      • the cilia in the trachea + bronchi pushes the mucus up to be swallowed
        • smoking paralyses the cilia, eventually destroying them
    • smoking causes lung diseases like lung cancer + enphysema
    • cigarette smoke contains carcinogens,tar + nicotine: all are harmful to the body


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