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How Does Co2 Get Into Our Bloodstream

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David H | 05:20 Thu 27th Dec 2012 | Body & Soul
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Although I know the body produces its own CO2 and is exhaled to keep the optimum 40mm pressure in the blood (that is easy to discover) I read this and similar passages which imply (no more or it would be clear) it also enters via breathing, and may be essential as the source:

" A person's breathing rate influences the level of CO2 in their blood. Breathing that is too slow or shallow causes respiratory acidosis, while breathing that is too rapid leads to hyperventilation, which can cause respiratory alkalosis. Although the body requires oxygen for metabolism, low oxygen levels normally do not stimulate breathing. Rather, breathing is stimulated by higher carbon dioxide levels."

http://en.wikipedia.org/wiki/Carbon_dioxide#Human_physiology

This is ambiguous to me, but appears to be saying the minimum CO2 level is required in air to stimulate the nervous system to breathe. So the basic question is, would we get sufficient CO2 into our bodies if it was absent from the air?
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Carbondioxide does not need to be present in the air we breathe in. When you breathe out, there is always over a litre of air left inside the lungs that will contain a much higher level of CO2 than atmospheric air. All movement of CO2 within the body is by diffusion. It diffuses from the tissues into the blood. It diffuses from the blood into the lungs. Diffusion...
10:36 Thu 27th Dec 2012
-- answer removed --
Our bodies make carbon dioxide. We need to breathe it out, not in.
\\This is ambiguous to me, but appears to be saying the minimum CO2 level is required in air to stimulate the nervous system to breathe. So the basic question is, would we get sufficient CO2 into our bodies if it was absent from the air?\\

We need a respiratory physiologist to answer this and that, I am not.

The respiratory centre (responsible for controlling respiration) is situated in the base of the brain and responds to CO2 levels in the blood.
No CO2...RC is depressed and breathing stops.

CO2 is formed in the tissues, passes in the blood through the RC, which it stimulates, through the veins to the lungs and exhaled.
Inspired air contains small amounts of CO2 (much less than 1%) but enough to keep the RC active.

Now \\\would we get sufficient CO2 into our bodies if it was absent from the air?\\\

I suppose, that the body COULD still breath with endogenous CO2, but the problem would be atmospheric factors, as with no CO2 in the atmosphere the external temperature would rise leading to the human body "burning up."

This is not a scientific answer, but you get my "drift."
LOL....just had another thought.....no one could not love for very long without CO" in the air, as "endogenous CO2" from muscle metabolism is always on the venous side and is exhaled in the lungs before the blood gets, via the arterial side, to the brain. The RC would stop and you would asphyxiate within a very short time....probably minutes after first going into spasms of tetany.
"love".....sorry i meant "live"..............I think;-)
Carbondioxide does not need to be present in the air we breathe in.

When you breathe out, there is always over a litre of air left inside the lungs that will contain a much higher level of CO2 than atmospheric air.

All movement of CO2 within the body is by diffusion. It diffuses from the tissues into the blood. It diffuses from the blood into the lungs. Diffusion requires a concentration gradient, so just how much diffuses through the alveolar walls depends on the concentration of CO2 in the alveolar air.

What the respiratory centre responds to, is not the CO2 in inspired air, but how much CO2 wasn't expired.

Slow breathing allows CO2 concentration to build up in the lungs thus slowing diffusion from the blood and leaving more behind, where it continues round the body via the arterial vessels and is detected by the RC which then increases the breathing rate.

On the other hand, rapid breathing flushes CO2 out of the alveoli as fast as possible, maintaining a high concentration gradient between the blood and air and optimising the outward diffusion of CO2 leaving very little in the blood to be detected by the RC which then slows breathing.
gen2 ...thanks....that sounds better than my answer.
David H also seems unclear what the source of CO2 is in the body.

CO2 is a waste product of respiration.
Respiration is the process by which energy is released from the food we have eaten.

In its simplest form:
sugars + Oxygen = Carbon-dioxide + water + energy.

CO2 is not needed and is exhaled.
Water just adds to other water in the body and is regulated via the kidneys.
The energy is what is needed by the body for movement, heat and metabolism.
Blimey, what's today - National Verbosity Day?
Sorry Rojash, I thought this was posted in 'Science', I forgot B&S was an offshoot of 'chatterbank'. I'll try to stick to short words next time I'm in here.
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Thanks all, I am on a project which although not essential to know this got it into a document which now can't be edited (their rules), so needed to check how far I'd drifted from accuracy. It's not the sort of thing you need to know normally or find if you do. I will mention the breathing into a bag scenario for increasing CO2 in a panic attack (no idea if it helps but people do it), and although the source is our own exhalation, we are still receiving it by breathing it in regardless. This may be an exceptional example, but does demonstrate we can also get it from breathing and wonder if there are any studies showing there is a proportion we all get from the air.

Fascinated by your other point sqad, how can removing CO2 from the atmosphere make the outside temperature rise? That's a new one to me.
May I repeat:
You get absolutely NO carbon dioxide from the air that you breathe in.

CO2 passes across body membranes by diffusion. Diffusion always takes place from where there is a high concentration to where there is a lower concentration. There is already a higher concentration of CO2 in the body than there is in the atmosphere. It diffuses out. You breathe it out. Exhaled air has up to 4% more CO2 than inhaled air.

Regarding the breathing repeatedly into a paper bag:
That does NOT put more CO2 into the body.
Someone having a panic attack may be hyper-ventilating and removing too much CO2 from the blood and thus increasing its pH (more alkaline).
Re-breathing your exhaled air from the paper bag DOES NOT put more CO2 into the body. What it does do, is to keep the concentration in the lungs at around 4% so there is no longer a steep concentration gradient between the blood and air. The CO2 already in the body does not get out. Since CO2 is being produced in the body all the time, the concentration in the blood rises and the pH lowers.

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