• Question: How is carbon dioxide removed from blood before it is exhaled?

    Asked by elliejayne to Aime, Akshat, Diana, Gemma, Judith on 23 Jun 2011.
    • Photo: Judith McCann

      Judith McCann answered on 20 Jun 2011:

      In your lungs there are absolutely loads of surfaces that are covered in a really thin layer of fluid, which is where gases (oxygen and CO2) are tansferred into the blood. The carbon dioxide is dissolved in the blood and passes through to this layer and is released as gas.

      This fluid layer is a contributing factor to why smokers can’t do as much excercise. Smoking dries out the layer so not as much gas can pass through-but its reversible…Not really relevant to the question, fun fact of the day 🙂

    • Photo: Akshat Rathi

      Akshat Rathi answered on 23 Jun 2011:

      Judith explained well. I will go little bit more in detail and explain how exactly does this exchange of gases happens.

      In the air there is about 21% Oxygen and 0.04% Carbon Dioxide. But in the air that you breath out there is about 15% Oxygen and 5% Carbon Dioxide. When these two gaseous mixtures come in contact in your lungs, there is natural driving force for equilibration to occur. Which is to say that the excess carbon dioxide inside the body needs to be transferred to the air and the excess oxygen in air needs to be transferred to the gases inside your body.

      This process occurs through diffusion. Best example of diffusion is what happens when you spray deodorant. You will see a fine spray of liquid coming out of the deodorant and then disappearing in the air if you aim it in the open. The molecules of the deodorant get spread very rapidly giving you a pleasant smell.

    • Photo: Gemma Sharp

      Gemma Sharp answered on 23 Jun 2011:

      The carbon dioxide we exhale diffuses from the blood vessels around the lungs into the lungs themselves. The reason it diffuses is that there is a higher concentration of carbon dioxide in the blood than the lungs, and carbon dioxide has a natural tendancy to move from areas of higher concentration to lower concentration 🙂

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