|We want to know is blood blue or red? It looks
blue in the inside and on the outside it is red.
|Question Date: 1998-01-23|
That's a good observation. When you see blood
outside the body it is usually a dark red. This
blood is from the veins. Sometimes you may cut an
artery. This blood is bright red. It also spurts
out in pulses instead of oozing like the blood
from veins. So even outside the body, blood can
be different colors. (What's the difference
between veins and arteries and why would that
affect the color? Why does arterial blood spurt?)
The blood vessels you see at the surface of your
skin are veins. Everyone's skin is slightly
different in color, so the veins can look
different in different people, but blood is
exactly the same color in everyone. It still
doesn't look red. That's because we're seeing the
*walls* of the veins too. When you see lemon-lime
flavored soft drinks in plastic bottles they
usually look green, but when you pour them out,
they're often clear or yellow. It's not the blood
that's bluish, it's the whole vein, including the
walls, just like the soft drinks look green
because they're in colored bottles.
you ever seen a totally white rabbit or mouse?
They're called "albinos" because they can't make
pigments (the substances that color our eyes,
skin, and hair). Their veins look red, even
though their blood is the same color as ours. Why
Your blood gets its red color from oxygen.Your
blood has this molecule in it called hemoglobin.
Hemoglobin is like a little transporter for
oxygen. It is used by your body to get oxygen to
your muscles. This starts when hemoglobin
attaches onto oxygen it gets from your lungs.
After that, your heart pumps your blood to your
muscles so they can use the oxygen. Then, your
blood returns to your lungs so that the hemoglobin
can pick up more oxygen.
attaches to a hemoglobin, the hemoglobin changes
"shape" and it looks "red". After that oxygen is
removed by your muscles, the hemoglobin changes
"shape" again, and this time it looks "blue".
So...when you're looking at your veins and
arteries, the ones that look "blue" have blood
without oxygen in them. The ones that look "red"
have blood with oxygen in them.
The current mythology is that arterial blood and
that exposed to the air (bleeding) is red because
oxygen binds with the hemoglobin resulting is a
red color. Venous blood is "bluish" because it is
oxygen depleted which results in a "blue" color.
The veins that carry the venous blood are just
under the skin hence this is the "blue" blood you
see. The arterial blood is carried in the
arteries which are deep in the body and not seen
through the skin. Also people who are suffocating
(oxygen depleted) turn "blue" because the blood at
the surface in the skin becomes oxygen depleted
and gives the body a bluish cast.
this helps. If I learn more I will pass it on.
You have a good question. The "color" of blood
depends on how much oxygen is in the blood; when
here is plenty of oxygen, the blood is more
"reddish in color. The reason that this is so is
because of a protein called HEMOGLOBIN, which
carries the oxygen in your blood. When hemoglobin
has a full oxygen load, it gives the blood a
reddish color. Here are a few questions for you to
1. Why is blood very bright
red when you get a cut? (Think about what is in
2. Do you think that blood coming
FROM the lungs will be more "red" or more "blue"
compared to blood that is coming BACK INTO the
To simply answer your question, it is because
of the science of light. The colors we are able to
see is due to the wavelengths of light that go
back into our eyes. We look at the veins which are
red, but the light that hits our skin that goes
back into our eyes for our brain to understand it,
is blue to our brain.
Your veins are not actually blue. They are a
dark reddish-brown, but appear blue because the
fat under our skin only allows blue light to
travel all the way down to our veins. Since it is
the only color of light that makes it to our
veins, it is the only color that is reflected, and
thus our veins appear blue! I hope this helps.
Your blood is actually always red! Blood in
your veins has very little oxygen and is a dark
red color that looks almost blue when covered by
your skin. Your arteries have bright red blood
because it has a lot of oxygen in it that is being
carried throughout your body to be used by
tissues. So it is your skin that is tricking you
into thinking your blood looks blue when in fact
it is always red.
A common answer to this question is that
deoxygenated blood in the body is blue and when it
comes to the surface (like when you get a cut) it
turns red so your veins look blue because your
body contains deoxygenated blood. Although it is
true that you have deoxygenated blood in your
body, it is not the reason why your veins appear
blue - your blood is NEVER really actually
blue. Deoxygenated blood is dark red and when
it comes to the surface it's red.
So back to your question about why your veins
don't appear reddish when looking at them from
your skin. It depends on a variety of things. One
is that the skin usually absorbs blue light;
subcutaneous fat, or fat beneath the skin, only
allows for blue light to be absorbed all the way
to your veins so your veins reflect back that way.
Also, since the blood in your body is a lot
darker, the veins appear darker. You may also
notice that different sized blood vessels appear
to be different colors. Another thing it can
depend on is how you see color and how your brain
perceives certain color against the color of your
If you're ever eaten meat or dissected an
animal you can see that veins aren't really blue,
they are in fact reddish in color.
A scientist suggested the following link in
order for you to learn more about blood vessels
here to read
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