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    Hi,

    I was going through an exam paper, and came across this question...

    "The concentration gradients of oxygen and carbon dioxide are maintained in the lungs during gas exchange. Describe how breathing and circulation achieve this. [5]"

    Any pointers on how to answer that for 5 marks?
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    (Original post by fjurble)
    Hi,

    I was going through an exam paper, and came across this question...

    "The concentration gradients of oxygen and carbon dioxide are maintained in the lungs during gas exchange. Describe how breathing and circulation achieve this. [5]"

    Any pointers on how to answer that for 5 marks?
    breathing achieves it by the lungs reducing the volume - increasing in presure so carbon dioxide is forced out. the muscules then relax increasing the volume so oxygen goes frm an high conc to low conc into the lungs. soz its wot i wud write lol.
    circulation - blood goes to the lungs for oxygen and at the same time exchanges it for carbon dioxide and the lungs breath the carbon dioxide out.
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    Don't forget the concluding phrase: Thus providing favourable concentration gradients for O2 and CO2 diffusion.
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    (Original post by 2776)
    Don't forget the concluding phrase: Thus providing favourable concentration gradients for O2 and CO2 diffusion.
    I don't think that answered the question. I reckon it has more to do with ventillation, because the circulatory system braches is parallel with the respiratory tree and the set up is analagous to blood flowing past a continually circulated pool of air - any answer should state how the difference (they call it a 'gradient', but that's a bit of a daft word to use) MAINTAINED, not just how it is set up.

    Ben
 
 
 

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