Gas exchange in the tracheal system of insects
- Created by: Kittykatty2000
- Created on: 26-03-17 16:07
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General:
- Have a tough exoskeleton through which hardly any gaseous exchange can happen
- Insects blood doesn't have a pigment that carries oxygen
- The gaseous exchange system of insects has evolved so oxygen is delivered to the cells and removes CO2 in the same way
Why do insects need a transport system?:
- Multicellular organisms
- High metabolic rate
- Low SA:VOL
- Diffusion wouldn't be quick enough
What features will their exchange surfaces have?:
- large SA:VOL
- Thin barrier
- Selectively permeable
Muscles expand in abdomen:
- Increase volume
- Decrease pressure inside
- Pressure outside > inside
- Air rushes in
Muscles contract in abdomen:
- Decrease volume
- Increase pressure inside
- Pressure outside < inside
- Air rushes out
Chitin - fibrous substance, not freely permeable
Tracheole - no chitin, elongated cells
Trachea - hollow tube
End of tracheole is tracheale fluid
Gas exchange:
- Along the thorax and abdomen are small openings called spiracles
- Air enters and leaves through these openings, but water is also lost
- The spiracles can be opened and closed to minimse water loss
- Behind the spiracles are the trachea - they carry air into the body and are lined with chitin which keeps them open when closed or bent
- Tracheoles come off the trachea
- These are smaller and permeable to gases
- They run between all cells so gas exchange can take place
- The extent…
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