Self Assessment Bio Q Hyperventilation

[member232]

If a pregnant woman is hyperventilating, what is the respiratory status of her fetus?

A. CO poisoned
B. CO2 depleted
C. O2 deprived
D. O2 enriched

Answer D

I chose answer D and completely understand why it's correct, but what's wrong with answer choice B? If you're hyperventilating, you're blowing off more and more CO2, and the PO2 is increasing, so shouldn't the CO2 status be depleted?

Or is that answer choice wrong because fetuses don't really need CO2 in the first place?

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[flashlightpen]

Sorry I don't know the answer to your question man - but could you please explain why it's D? I'm trying to understand too <3

 

[PanRoasted]

While I don't know the exact reason for this, I would assume that because a fetus transfers nutrients blood to blood (mother's blood - fetus blood), and fetuses have hemoglobin that binds more tightly to O2 than adult blood, the overall respiratory status of the fetus would be more heavily weighted toward O2 enriched vs. CO2 depleted. The CO2 status of a fetus is probably less linked to the mother's CO2 status than is the O2 status of the fetus to the O2 status of the mother. That's just my guess.

EDIT: The correct answer is D because the mother's blood is highly O2 enriched because she is hyperventilating AKA blowing off CO2, raising the pH of her blood, and therefore increasing her hemoglobin's affinity for O2, meaning her hemoglobin is highly O2 saturated/enriched. This translates to baby having a lot of O2 in its blood due to the exchange process of nutrients between fetal and maternal blood, as I described above.

 

[member232]

@ Panroasted
Yeah explanation was vaguely hinting at that connection.
And also technically, you would WANT the umbilical system to deplete the fetus of wastes (e.g.) carbon dioxide...

@ Flashlightpen

Hyperventilation is when the body's respiration rate is increased. If you're breathing rapidly, you're taking in lots of O2 and blowing off lots of CO2... thus you're increasing the amount of oxygen in your body while decreasing carbon dioxide. This correlates to the gases available for the fetus for a pregnant mother. If there's more oxygen in her circulation, more oxygen will be available for transfer to the fetus, and fetal hemoglobin, with its higher affinity will bind to this extra oxygen, giving it a status of "oxygen enriched"

 

[flashlightpen]

Thanks guys! Hope you got your question answered too member232 =)