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Author Topic: Why is blood a different RED when comparing a nosebleed to blood test vial?  (Read 10202 times)

Offline beem

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Both the nosebleed and the blood test vial are fresh blood.

So why is a nosebleed a bright red colour and the vial looks dark purple, like it contains prune juice?


 

Offline Chemistry4me

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Hmmm...prune juice :P:P:P
 

Offline Chemistry4me

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On a more serious note:
You mean (the colour of the blood) like the one on the right?

 

Offline beem

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The prune juice merely references my age ;D

Re the blood colours, it obviously has something to do with oxygen.
A recent nosebleed was a lot lighter in colour than the contents of my blood test vial today.

If oxygen is indeed involved, wouldn't the nosebleed blood be darker than the fresh blood in the vacuumvial?

...it's very good of you to provide...a...er...graphics  [:0]


 

Offline Chemistry4me

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Oxygenated blood is scarlet red in colour, deoxygenated blood is dark red.
 

Offline Chemistry4me

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What happened at your blood test? I mean, what did they do with your blood?
 

Offline Chemistry4me

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...it's very good of you to provide...a...er...graphics  [:0]
But was I correct? Was your blood sample like the one on the right?
 

Offline beem

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Quote
Oxygenated blood is scarlet red in colour, deoxygenated blood is dark red
I thought it would've been the reverse.
Yes, the blood sample more closely resembled the colour at right.
Maybe even darker.

Or maybe I'm thinking of rust.   ;)

What they did with it?
Gee, maybe they're punctuating THEIR forum sentences with it  ;D ;D
Part of annual probe/poke.

 

Offline Chemistry4me

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A bust nose will be from an artery(s) so that'll have oxygenated blood (scarlet red), when they took your blood sample it would have been from a vein so it would be darker red in colour.
 

Offline beem

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I still think the noseblood would give them more information, i.e. pollution levels, or whether I have a cat or dog, and so on.

Just a little difficult to give noseblood on command at 8 a.m. in the lab.  [xx(]
 

Offline Chemistry4me

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Hmmm... do you get nose bleeds often? Because if you do, you might like to contribute to this thread.
 

Offline beem

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Fortunately, no, I don't.

I'm congratuling myself  ;Dfor resisting the urge to ask how you were able to come up with your...er....a...graphics

Cheers!

 

Offline chris

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You've pretty much got to the answer.

The nose receives a very rich blood supply and when the nasal mucosa (lining) is traumatised the superficial capillaries supplying the tissue are damaged. The blood that escapes is highly oxygenated, making it look redder.

Venous blood, by comparison, is more deoxygenated because it has already flowed through a capillary bed and released its oxygen to the tissue and picked up carbon dioxide. The reduction in oxygen makes the haemoglobin molecule change shape, affecting the wavelengths of light it reflects causing it to look darker.

Chris
 

Offline beem

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Thanks ever so much!
 

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