Oxygen respiratory question

rhan101277

rhan101277

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Ok, so the air we breathe in contains 21% oxygen. When we exhale, we exhale 16% oxygen. So the body only uses 5%? I guess this must be sitting still. Obviously if you are running, doing labor work you breathe faster because your body needs more oxygen. As you exert yourself, does your body just continue to use the same amount, but you breathe fast to sustain your low carbon dioxide percentage.

When giving 100% oxygen to someone is it feasible that 95% of it is exhaled, if so when why give oxygen? I know it is pounded into our heads, but I want to know why. Besides the fact that someone could be suffering from respiratory distress or heart issues, how can it help.
 
If a patient is able to breath in less air, it might be a good idea to increase the percentage of oxygen of that air.
 
If you take into account the dead space in the respiratory system, then the body is absorbing a little over 7% of the O2 in the air, assuming the 16% figure comes from the average of the O2 in the exhaled air.

Like firecoins said though, a higher concentration of O2 means a pt needs to move less air to get the required amount of O2. This is good if they have something like a couple broken ribs, and breathing deeply causes lots of pain and possibly more damage. If a pt has a respiratory disease and can't process as much air in the lungs then a higher concentration of O2 will help as well.
 
Yeah thats a good site. I am in kindergarden as far as medicine is concerned. I didn't realize anesthesia had such effects.
 
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remember too that all the air in the lungs isn't necessarily available for exchange with the blood. remember the difference between respiration and ventilation. ventilation is moving air in and out of the lungs. respiration is the exchange that takes place at the cellular level where oxygen and carbon dioxide are exchanged.
think of it like a balloon. only the air next to the membranes actually is available for exchanges. the rest is "filling" the space. because of this the more O2 that you can put in the lungs means the more likelihood that the exchange will take place. and like firecoins said again the less air they need to move. :)
 
Katie said:
remember too that all the air in the lungs isn't necessarily available for exchange with the blood. remember the difference between respiration and ventilation. ventilation is moving air in and out of the lungs. Diffusion is the exchange that takes place at the cellular level where oxygen and carbon dioxide are exchanged.
Click to expand...
Rate of diffusion is dependent on a variety of things, including thickness (edema), surface area (various shunts, other pathologies), and concentration gradient (helped by supplemental O2). Respiration is the cellular process by which glucose (and other sugars) is converted into CO2 (and other assorted goodies) producing adenosine triphosphate (ATP) (the "energy currency" of the cell).
 
JPINFV said:
Respiration is the cellular process by which glucose (and other sugars) is converted into CO2 (and other assorted goodies) producing adenosine triphosphate (ATP) (the "energy currency" of the cell).
Click to expand...

isn't that cellular respiration? my textbook defines respiration as "the exchange of oxygen and carbon dioxide between an organism and the environment." pulmonary ventilation is air "moving into and out of the lungs." the mechanism is diffusion which is a passive process moving molecules from an "area of higher concentration to an area of lower concentration." so wouldn't diffusion be the mechanism by which respiration takes place?
 
^
My bad... I just looked it up to check. I've only really seen respiration to refer to cellular respiration though.
 
Consider also altitude.

While the gas mix remains the same from Dead Seas to Everest (I emailed a NOAA scientist to confirm that a few years ago), the pressure varies and you can get some real changes not only from one elevation to another (I have seen some real changes at even a four thousand foot climb) but how long the patient has been at that altitude. I'm not going near barometrics again, but suffice to say more O2 will help, and help even more at altitude. (:blush:Yes, and even if they have the bends).
 
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