Friday, 22 February 2013

2.46 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood in capillaries

The alveoli have are thin, this allows gasses to diffuse through them easily.
They are small and there are many of them meaning there is a large surface area through which much gas can diffuse at once. It also means there is a lot of surface in contact with the blood stream for gasses to diffuse into.
Alveoli have a moist lining for gasses to dissolve into.

14 comments:

  1. Is there any chance of a corrected first sentence as I can't figure out what it is supposed to say. Thanks a bunch for all these by the way your a real life saver!

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  2. TRIMM!!!!
    Thin Wall
    Rich capillary network
    Increased surface area: volume ration
    Moist
    Moving blood

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  3. In a normal person the alveoli have lots of folds in them to increase surface area further (with emphysema the alveoli walls break down getting rid of the folds meaning the person has difficulty with getting enough oxygen)

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  4. just wanted to say that the walls are 1cell thick so a short diffusion distance for the exchange of O2 and CO2 but thanks hanna!!

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  5. The Biology Syllabus has changed.... New Syllabus Blog:

    http://igcse-biology-2017.blogspot.hk

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  6. more at

    http://igcse-biology-notes.blogspot.hk/2017/06/246-understand-role-of-intercostal.html

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