• Set Yourself Up For Success Webinar

    October 6, 2021 at 2 PM Eastern/11 AM Pacific
    SDN and Osmosis are teaming up to help you get set up for success this school year! We'll be covering study tips, healthy habits, and meeting mentors.

    Register Now!

  • Funniest Story on the Job Contest Starts Now!

    Contest starts now and ends September 27th. Winner will receive a special user banner and $10 Amazon Gift card!

    JOIN NOW
  • Site Updates Coming Next Week

    Site updates are coming next week on Monday, Wednesday, and Friday. Click the button below to learn more!

    LEARN MORE

Resp Physio Question

Lindyhopper

Senior Member
10+ Year Member
5+ Year Member
2+ Year Member
7+ Year Member
Jun 13, 2004
586
0
201
I've always been confused about something about gas exchange. If anyone wants to take a crack at it much appreciated.
It's probably better for me to first consider the gas exchange at hard working tissue. The CO2 generated combines with H2O in the RBC --> H2CO3 --> H+ + HCO3- . All the texts all say that this increases H+ conc. thus lowering blood pH.
My confusion stems from the fact that H+ binds Hb (or other proteins); stabilizing the tense conformation in Hb. Meanwhile, HCO3- is exchanged into the plasma for CL-. I don't understand why this doesn't raise blood pH. The H+ remains bound to the Hb while the HCO3- is free to "soak up" plasma H+'s.
Thanks, for any help.
 

SeventhSon

SIMMER DOWN
10+ Year Member
7+ Year Member
Aug 23, 2005
1,022
1
0
37
San Diego
  1. MD/PhD Student
the answer lies in the fact that HCO3- is not a great base.

ie this reaction isn't that strong HCO3- + H20 -----> OH- + H2CO3

HCO3- does soak up acid, but the fraction of H+ that does not move into cells to be buffered has a larger effect on the pH. Matter of fact, you can probably view the generation of a bicarb into the serum as the reason (or one of the reasons) that intracellular buffers help keep the blood pH higher than it would be without buffer.

If you think about it another way... it takes mM changes in bicarb to change pH, but it only takes nM changes in H+.
 
About the Ads
This thread is more than 13 years old.

Your message may be considered spam for the following reasons:

  1. Your new thread title is very short, and likely is unhelpful.
  2. Your reply is very short and likely does not add anything to the thread.
  3. Your reply is very long and likely does not add anything to the thread.
  4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
  5. Your message is mostly quotes or spoilers.
  6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
  7. This thread is locked.