Insects

• How do insects increase gas exchange when active?

  -When active- lactic acid accumulates in muscles produced by anaerobic respiration

  -this reduces the water potential of the muscles and fluid is withdrawn from the ends of the tracheoles ny osmosis

  -Air moves into the tracheoles to replace the volume occupied for fluid and gases diffuse more rapidly accross the air-filled tracheoles
• Explain 3 ways in which an insect's tracheal system is adapted for effeicent gas exhange

  -traceholes have very thin walls so gases ahve short diffusion pathway

  -tracheoles are heavily branched increasing surface area for gas exchange

  -tracheoles are fluid-filled which moves into cells during high activity

  - so faster diffusion of O2 into muscles
• Preventing Water loss

  -can close their spriacles

  -Waxy coating on exoskeleton to reduce evaportion and increase diffusion distance

  -Tiny hairs around spriacle trap water vapour to reduce water loss by reducing water portential gradient