Gas Exchange in Insects

• How do Insects get Oxygen to their muscles?

  Through their skin by diffusion
• Why cant’t insects just use their body surface for gas exchange?

  • Terrestrial - lose too much water
  • Too metabolically active
• How do insects minimise water loss?

  • Cuticle Layer
  • Small Surface Area to Volume ratio
• What is the order of Gas Exchange System?

  • Spiracles
  • Trachea
  • Tracheoles
• How are gases moved through the tubes?

  Oxygen and CO2 move through still air down a concentration gradient

  • respiring cells will have a high concentration of CO2 outside themself, creating a steep concentration gradient from themself to the outside air
  • They will also be using a lot of oxygen, so there will be a steep concentration gradient from the outside air to themself
• How are gases moved through the tubes?

  • Beating their wings creates a mass flow of oxygen
  • Air can then be pushed through a downward motion of the wings
  • Abdominal pumping can also push air out
• Hope are gases moved through the tubes (Water)?

  • Ends of tracheoles are filled with water
  • Anaerobvic respiration releases lactic acid which lowers water potential of the cells
  • Water moves into these cells, pulling the air through