The colour of blood...

[Jon_in_london]

Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

 

[geni]

Well you can see that your veins are blue so you should be able t see the difference. I remember My biology tescher mentioning that before they brough in some of the more recent safly regs he used to do a demostration involving bubbleing CO2 and O2 through a test tube of blood and you could see a difference.

 

[Rolfe]

Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

Spectra is plural. Spectrum is singular. Spectras is ungrammatical. End of lecture.

Yes you can tell the difference.

Doing a post-mortem, the blood comes out of the veins and pools on the table, dark red. As it is exposed to the air it develops a bright red film of oxygenated blood. Very obvious to the naked eye.

If you're taking a blood sample and aiming for venous blood, the other thing which tells you you've hit an artery (apart from your patient kicking you in the teeth) is that the blood in the syringe is bright red.

And that's animal blood. Human venous blood is weird, it's so dark it's not really red at all, it's almost black. So I think the difference will be even more obvious. If you cut a finger, that's capillary blood, which is sort of in between, quite oxygenated really, and of course it is in contact with the air so that also has an effect. If you've ever had a blood sample taken, though, or given blood, it's easy to see that the blood coming out of the vein into the syringe or collection pack (and so not exposed to the air) is very dark.

OK?

Rolfe.

 

[Hand Bent Spoon]

People who own grammar manuals NEVER own etiquette manuals

^Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.

Correcting someone's etiquette, even when they commit a faux pas, is impolite unless you are their parent or etiquette coach. So shame on me.

 

[LucyR]

Re: People who own grammar manuals NEVER own etiquette manuals

Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.

'advise'?

 

[roger]

Oh, this thread is going to get ugly. And fast.

 

[espritch]

Oh, this thread is going to get ugly. And fast.

Yeah. If it continues in this vein, it could coagulate into a regular blood bath. And wouldn't that be humorous?

 

[davefoc]

I thought the question was very interesting and I was interested in the response. Thank you Rolfe.

I don't think, it was mentioned but I am under the impression that the notion that blood is ever blue is false and that any blue appearance is because we see the blood in our veins through our skin (usually).

 

[Cecil]

Yeah. If it continues in this vein, it could coagulate into a regular blood bath. And wouldn't that be humorous?

Now you're getting to the heart of the matter. But, I'm still sanguine about the outcome of this thread - I don't think blood will be spilt.

 

[LucyR]

Now you're getting to the heart of the matter. But, I'm still sanguine about the outcome of this thread - I don't think blood will be spilt.

Yes, fortunately blood's thicker than water.

 

[Zep]

I thought the question was very interesting and I was interested in the response. Thank you Rolfe.

I don't think, it was mentioned but I am under the impression that the notion that blood is ever blue is false and that any blue appearance is because we see the blood in our veins through our skin (usually).

If I recall, "blue blood" looked blue simply because the owner's skin, through which their veins showed, was usually a very pale (i.e. pasty) white. That is, they were upper classes, hence "bluebloods". As opposed to the lower classes whose skin was was stained much darker brown due to long hard days gathering muck on the muck-farms to be shipped to the muck-factories.

Or so I was told.

 

[espritch]

Just as a point of interest, the blood of horse shoe crabs really is blue. IIRC it is copper based rather than iron based.

Sorry to interupt the bloody pun fun, but I had a feeling that topic had about been bled dry anyway.

 

[JamesM]

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

Absorption spectra for all sorts of states of haemoglobin can be found here:

http://www.medphys.ucl.ac.uk/research/borg/research/NIR_topics/spectra/spectra.htm

Why not plug 'em into a spreadsheet and have a look? I tried it with adult hbO2 and hbCO, and they were indeed different. No idea if that's different enough to detect by eye, but if Rolfe says yes, that's good enough for me.

 

[Rolfe]

Would it help if I said sorry?

I once saw the item "Gateaux's" on offer in a cafeteria in St Peter Port, and I think it scarred my psyche for life.

Your repentant,

Rolfe.

 

[Ladewig]

Shame on me

Correcting someone's grammar/spelling when you are not their parent or teacher is impolite (unless such advise is asked for). So shame on you.

Because "someone" is singular and "their" is plural, you have violated the pronoun/antecedent rule.

 

[davefoc]

Because "someone" is singular and "their" is plural, you have violated the pronoun/antecedent rule.

Does this rule still apply today? Previously, the acceptable wording might have replaced "their" with "his", but I think today's style is to avoid the use of "his" where it describes something that belongs either to a male or a female.

 

[Cecil]

Does this rule still apply today? Previously, the acceptable wording might have replaced "their" with "his", but I think today's style is to avoid the use of "his" where it describes something that belongs either to a male or a female.

I think the language is changing. Their seems to be becoming more and more accepted as a singular pronoun, to avoid the awkward yet politically correct term "his or her".

 

[Camillus]

Is it possible to tell the difference between oxy- and carboxy haemoglobin with the naked eye.

Methinks not.

Anybody know the absorption spectras and whether they are different enough to be discernable with the naked eye?

You're right: you can't tell the difference with the naked eye. You can infer that the bright red colour is COHb from the circumstances but there is no discernible visual difference, in my experience, between well oxygenated blood and blood with a high CO content.

Cheers

 

[Rolfe]

Re: Re: The colour of blood...

there is no discernible visual difference, in my experience, between well oxygenated blood and blood with a high CO content.

Er, CO content? We were talking about CO<SUB>2</SUB> content, unless I've totally got hold of the wring end of the stick.

And in my experience the colour of that is quite different. Carbon monoxide poisoning is another matter which I didn't think anyone had raised.

The blue-blood thing has been well explained. Venous blood does look blue-ish when seen through thin, white, non-sunburned skin.

(I think the "their" thing is acceptable, but the use of "advise" when "advice" was meant, is om mare shaky ground.)

Rolfe.

 

[Camillus]

Re: Re: Re: The colour of blood...

Er, CO content? We were talking about CO<SUB>2</SUB> content, unless I've totally got hold of the wring end of the stick.

And in my experience the colour of that is quite different. Carbon monoxide poisoning is another matter which I didn't think anyone had raised.

I think you've got the wrong end of the stick . Carboxyhaemoglobin occurs in the presence of CO . CO<SUB>2</SUB> produces carbaminoglobin, since it binds to the globin rather than the haem part of the molecule.


Cheers