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Anonymous asked in Science & MathematicsBiology · 1 decade ago

Urban Myth or Truth: human blood is blue when inside the body and turns red only when it reacts with air?

38 Answers

  • Anonymous
    1 decade ago
    Favorite Answer


  • Anonymous
    6 years ago

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    Urban Myth or Truth: human blood is blue when inside the body and turns red only when it reacts with air?

    Source(s): urban myth truth human blood blue body turns red reacts air:
  • ?
    Lv 4
    4 years ago

    Blue Blood Myth

  • 1 decade ago

    I always thought that it was true that blood became red after it reacted with air, and it was blue inside the body. My wife just took an anatomy and physiology class (she's studying to be a nurse) and she just told me the other day that it was a myth.

    She said the reason why people think it is blue is because of the color of the veins. So don't believe anyone who is telling you different.

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  • 1 decade ago

    Myth. Human blood is always red. Two ways to prove this:

    Donate blood. The blood is taken directly from a vein and never hits oxygen, yet is a deep maroon.

    Hold a flashlight to the palm of your hand and look at the back of it. Red. No blue blood shines through; because it doesn't exist (unless you're a horseshoe crab).

    Our veins appear blue through our skin because of the way our skin color cancels out red, hence why you can't usually see arteries.

  • Anonymous
    8 years ago

    Human blood is NEVER blue, EVER. Anyone who says otherwise VERY uneducated. Just watch a video of surgery being done with a scope. CLEARLY the blood is red. Oxygenated of not it's never blue. It does change the hue from a dark read to a light red. But NEVER to or from blue.

  • 1 decade ago

    It's a myth. Veins in the skin appear blue for a variety of reasons only weakly dependent on the colour of the blood. Light scattering in the skin, and the visual processing of colour play roles as well. blood is continuously red ranging from bright red when oxidised to dark red when free of oxygen.

  • 7 years ago

    Sorry guys, but most of you are wrong. Blood is always red. Arterial blood is bright red, due to the high amounts of oxygen and the bond it forms with haemoglobin, but even when oxygen depleted, blood is still red, albeit a darker shade of red. Blood cannot simply be oxidised when it comes into contact with air, it is a complex process.

  • Anonymous
    7 years ago

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  • Anonymous
    1 decade ago

    I am absolutely staggered by the number of people who actually believe that deoxygenated blood is blue.

    No, human blood is *never* blue.

    Even when totally depleted of oxygen, it becomes a dark red colour (some might call it maroon). If you were to see a car or a paint strip that colour, you would say it was red.

    Fully oxygenated (arterial) blood is bright red. Depleted (venous) blood is dark red. NOT blue.

    The only time blood is ever blue is in mollusks and some arthropods, which utilize copper in the molecule that carries oxygen to the their tissues (hemocyanin), instead of iron as vertebrates do (hemoglobin).

    The veins through your skin only look blue because of diffusion of the light while passing through layers of tissue. In actuality, they're more of a greyish, white colour. You don't normally see arteries through the skin because they tend to be buried deeper in the tissues, but they're pretty much the same colour (but thicker walled, with higher blood pressure).

    The idea that human blood is blue is absolutely a myth.

  • 1 decade ago

    Myth. Probably originated from the fact that veins look blue when people look at them through their skin! However, all blood is definately red, whether in contact with oxygen or not.

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