Respiration

• Nasal passages

  air is filtered, moistened and warmed
• Trachea


  The pipe that takes airto the lungs

  contains cartilage for support
• Bronchi


  delivers air to the bronchioles
• Bronchioles

  Delivers air to the alveoli
• Alveoli

  site of gaseous exchange
• Inspiration


  • Intercostal muscles contract
  • ribs move up and out
  • diaphragm contracts and flattens
  • pressure in thorax decreases
  • air fills lungs
• Expiration 


  • Intercostal muscles relax
  • ribs move down and in
  • diaphragm relaxes and returns to dome shape
  • pressure in thorax increases
  • Volume of air decreases
• Order of organs when we exhale

  • Alveoli
  • bronchioles
  • bronchi
  • trachea
  • nasal passage/mouth
• Equation for respiration

  glucose + oxygen —> energy + carbon dioxide + water
• Respiration produces energy by…

  … burning the glucose we eat using the oxygen we inhale
• Burn energy

  Transport oxygen to cells

  oxygen travels in the blood
• Alveolus characteristics

  • Alveolus one cell thick
  • capillary wall one cell thick
  • millions of alveoli
  • thin layer of moisture
• alveolus characteristics explanation

  thin- short diffusion distance

  moisture- reduce friction and gases dissolve

  blood capillary- alveolus has blood capillary

  lots of alveoli- increase surface area
• chemicals in cigarette smoke

  • tar
  • nicotine
  • carbon monoxide (CO)
• nicotine

  addictive
• carbon monoxide

  • odourless and tasteless
  • car exhaust fumes
  • combines with haemoglobin