gas exchange in insects

• gas exchange systems in insects


  many insects are very active during parts of their life cycles

  relatively high oxygen requirements

  however, they have a tough exoskeleton through which little or no gaseous exchange can take place

  don't usually have blood pigments that carry oxygen

  the gaseous exchange system of insects has evolved to deliver oxygen directly to the cells and remove carbon dioxide in the same way
• Spiracle


  An opening in the exoskeleton of an insect which has valves and allows air to enter the insect and flow into the system of tracheae
• Tracheal system of an insect


  • Rigid exoskeleton with waxy coating that is impermeable to gases
  • Delivers oxygen directly to all organs and tissues
  • Tracheae are tubes that lead to narrower tracheoles
  • Rigid rings of chitin keep the tracheae open
  • Tracheoles run between cells and into muscle fibres, the site of gas exchange
• For smaller insects, the tracheal system provides sufficient oxygen via diffusion
• Tracheal system


  Breathing system in insects that delivers oxygen directly to all organs and tissues
• Insect exoskeleton


  • Rigid with a waxy coating that is impermeable to gases
• Spiracle


  Opening in the insect exoskeleton with valves that allows air to enter the insect and flow into the tracheal system
• Tracheae


  Tubes within the insect respiratory system which lead to tracheoles
• Tracheoles


  Narrower tubes within the tracheal system, the site of gas exchange
• Rigid rings of chitin keep the tracheae open
• Ventilation mechanism in active, flying insects


  1. Closing the spiracles

  2. Using abdominal muscles to create a pumping movement for ventilation

  3. Drawing fluid at the narrow ends of the tracheoles into the respiring muscle so gas diffuses across quicker