Given our seemingly permanent obsession with all things vampire,
chances are you've been exposed to some kind of love sick, brooding, vampire heartthrobs on a screen somewhere.
And whether those are pretty vamps slurping blood from nubile necks,
sipping it from antique goblets or splattering it on walls.
The blood itself, whether crimson, burgundy, or bright red,
is kinda hard to miss.
The shade of that blood may vary, but the blood out in the open air
Is. Always. Red.
And yet, when you look down at your wrist you see
the blood in your veins is bluish.
What?!
So, what, color, is the blood in your body really?
Before we answer that question though, I wanna talk a little bit about more what your blood is made of.
Blood, is the fluid that our hearts pump through our circulatory systems to deliver
oxygen, and other materials to all the cells in our body.
The average adult human has about five liters of blood sloshing around inside it,
and that fluid is made up of clearish liquid plasma,
in the red and white blood cells and platelets that float within it.
You probably know that white blood cells fight off infection,
platelets help blood clot,
and the red blood cells carry oxygen.
Red blood cells are one-third hemoglobin,
an iron-rich protein that binds to oxygen and gives our blood it's rusty red hue.
And Hemoglobin, is a kind of Hemochrome, a protein that largely influences blood's color.
Different organisms use different proteins,
and not all animals use Hemoglobin,
so not are animal's blood is red.
Which means that your blood color depends on what you are, and how your blood moves oxygen around your body.
For example, most mollusks including Octopi, squid, snails, slugs, and some arthropods,
bleed blue blood.
This, is because their blood contains higher levels at Hemocyanin,
a copper-containing protein that turns from basically colorless to dark blue when exposed to oxygen.
Certain marine worms use Hemerythin to transport oxygen in their blood,
which turns a pinkish violet color when oxygenated.
There's even a genus of skinks, in New Guinea,
that have green blood because of a build up of a greenish pigment known as Biliverdin,
a byproduct of the breakdown of hemoglobin.
You've actually seen a little burst of Biliverdin in your own body.
It's the stuff that makes a three-day-old bruise look green.
An excessive of it can lead to Jaundice and yellowing of the skin pigments,
but, back to your blood.
There's been a long-standing misconception that human blood is blue
until it hits the open air and gets oxygenated to it's crimson hue.
That is not true.
Unless you've been hitting up Willy Wonka's magic blueberry gum your blood,
is never blue.
Whether exposed to air by accident, at the cutting board, or safely contained within your body, your blood,
is always red.
It only appears blue in your veins from the outside because of the way different light wavelength penetrate your skin.
It is true that the blood in your arteries and capillaries are a brighter red in the deep red blood in your veins,
which has to do with how recently that blood picked up new oxygen.
I actually once had a phlebotomist take blood in my veins and then she said:
"watch this"
and she shook it up, and I could see the color change.
It was really cool, but it did not go from blue to red!
So here's how it goes: your heart sends blood through your lungs to grab an oxygen snack,
then pumps it through your arteries and all your capillaries where it delivers that oxygen
to cell tissues everywhere.
As your blood rides through your veins,
on its way back to your heart it's just, like, darker because it has delivered that oxygen.
You may have noticed the difference last time you got a papercut.
Maybe you took notice that the blood coming from a little cut on your finger seemed lighter and brighter
than the darker, syrupy-looking blood you saw coming from your forearm at a blood drive
The blood from your papercut was capillary blood and was full of oxygen,
while the stuff that the phlebotomist tapped at the blood drive,
was venous blood that had just delivered its oxygen payload.
There's slightly different shades of red because they're in different phases of the oxygenation process.
but they are both still, decidedly,
Not. Blue.
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