Bohr Shift

[Yope]

I understand that via this reaction:

CO2 + H20 ---> HCO3 + H+.

Also, the oxygen dissociation curve shifts to the right in presence of increased [H+], thereby unloading more O2 where it is needed (active muscle tissue, for example).

However, my confusion involves bicarbonate. Doesn't it buffer the blood and prevent any fluctuations in pH, and thus, keep the [H+] constant?

Thinking of the Bohr shift as a result of lactic acid build up in muscle makes more sense, but I don't understand this contribution of CO2.

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[thatscorrect7]

H20 + CO2 --> H2CO3 --> H + HCO3- --> 2H + CO3 (2-)

Buffer Solution

 

[Yope]

Isn't HCO3 much weaker an acid? Would there be that significant a change?

 

[Institute]

correct me if i'm wrong but even though hco3 acts as a buffer, it is the accumulation of co2 that is leading to the o2 dissociation curve to the right. why? because the lungs are where you exhale your co2 and if you're not exhaling it, you're accumulating it, meaning that pCO2 is going up and pH is starting to decrease. you can offset this with an infusion of bicarb or by hyperventilating.

i'm probably missing stuff, but whatever. other people can fill in the blanks.