Insect

• Pathway


  . 1 Spiracles

  . 2 Tracheae

  . 3 Airsac

  . 4 Tracheoles

  . 5 Muscles/organs
• Spiracles


  . Holes along exoskeleton

  . Open and close to prevent water loss

  . Hairs to trap water
• Tracheae


  . Tubes branched from Spiracles

  . Rigid rings like cartilage to keep air ways open
• Tracheoles


  . Branched tubes from the tracheae that deliver oxygen past other cells straight to muscles+organs 

  . Lots of them, large SA

  . Short diffusion pathway to other cells
• Air-sac


  Some insects use their abdominal muscles to squeeze their trachea system so it is lower than atmospheric pressure inside, so when released sucks air into the air sack 
• Extra adaptation 


  When at rest, water seeps across the muscles in the tracheoles, when the wing muscles contract for flight it is partially anaerobic and lactate builds up, lactate is soluble, this lowers the water potential, water passes into the muscles via osmosis, this draws air from the tracheoles closer to the muscles for a shorter diffusion pathway
• Insect facts


  . Usually fly or jump, high metabolism, high oxygen demand for energy

  . Exoskeleton- waxy+waterproof, good to prevent water loss, bad for diffusion
• Picture 


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