insect gas exchange

• gases enter and exit insects by spiracles in their skin
• spiracles are closed when not breathing so water loss is reduced
• the walls of tracheal system are thin so gases diffuse easily across them
• Insects use muscles to increase rate of breathing processes
• spiracles (insects)= holes on the surface of the body which can be opened and closed by a valve for gas or water exchange
• tracheal tubes (insects)= large tubes extending through all body tissues , supported by rings of chitin
• tracheoles (insects)= smaller branches from the tracheal tubes
• tracheoles have fluid at the ends to make gas exchange more efficient - Fluid in the end of the tracheoles allows oxygen to dissolve to aid diffusion and reduces water loss.
• explain gas exchange in insects:

  • gases move in/out of the tracheal tubes through spicicles
  • a diffusion gradient allows O2 to diffuse into body tissue while co2 diffuses out
  • the contraction of the muscles in the tracheal tubes allows the movement of air in and out
• 1. Air enters the tracheal system through open spiracles.
  2. Air moves into larger tracheae and diffuses into smaller tracheoles.
  3. Tracheoles branch throughout the body, transporting air directly to cells.
  4. Oxygen dissolves in water in tracheal fluid and diffuses down its concentration gradient from tracheoles into body cells.
  5. Carbon dioxide diffuses down its concentration gradient out of body cells into the tracheoles.
  6. Air is then carried back to the spiracles via the tracheae and released from the body.