Insects gas exchange

• Insect system:

  spiracle - tracheae - tracheoles - fluid - body cells
• Insects ventilation:

  Abdomen expands - volume increases = pressure decreases below atmospheric

  • abdomen spiracles are closed
  • thorax spiracles are open so air enters down a pressure gradient

  Abdomen compresses - pressure increases = volume decreases

  • abdomen spiracles are open so air exits down a pressure gradient
  • thorax spiracles are closed
• Insects ensure they have an efficient supply of oxygen to their tissues by exposing cells directly to the oxygen through the tracheal system