Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: beem on 03/02/2009 03:50:56

Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 03:50:56
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?
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 03:58:02
Hmmm...prune juice [:P][:P][:P]
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 04:09:53
On a more serious note:
You mean (the colour of the blood) like the one on the right?

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.biophotonicsworld.org%2Fuploads%2F0000%2F0043%2FNIK_3232-Drops_of_blood_medium.JPG%3F1212000434&hash=87f9e1f6e65a904d006048cb18fd9b26)
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 06:12:05
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]


Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 06:17:35
Oxygenated blood is scarlet red in colour, deoxygenated blood is dark red.
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 06:18:32
What happened at your blood test? I mean, what did they do with your blood?
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 06:26:00
...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?
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 06:32:35
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.

Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 06:35:38
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.
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 06:46:01
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(]
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: Chemistry4me on 03/02/2009 07:03:52
Hmmm... do you get nose bleeds often? Because if you do, you might like to contribute to this (http://www.thenakedscientists.com/forum/index.php?topic=19532.0) thread.
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 18:40:55
Fortunately, no, I don't.

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

Cheers!

Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: chris on 03/02/2009 18:52:39
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
Title: Why is blood a different RED when comparing a nosebleed to blood test vial?
Post by: beem on 03/02/2009 20:22:35
Thanks ever so much!