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Hemoglobin curve question

Discussion in 'MCAT Discussions' started by redsoxfan, Aug 7, 2006.

  1. redsoxfan

    redsoxfan Senior Member
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    There's a question on the Kaplan #4 exam that's really bugging me. I don't understand the "correct" answer and why I'm wrong. The gist is basically this: Compensatory mechanisms for acclimatizing to high altitudes would cause the Hb/O2 curve to shift: I said to the right, but the answer says to the left. What do you guys think??
    thanks!
     
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  3. geno2568

    geno2568 Senior Member
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    the air has less O2, so their needs to be a higher affinity so that it can bind to it better in the lungs
     
  4. ChymeChancellor

    ChymeChancellor Membership Revoked
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    I also got that wrong when I took it last spring. The answer I guess wants the compensatory mechanism.... So, to compensate for the lower O2 at the higher altitude, the curve shifts to the right so you will only need a lower pO2 to achieve the same saturation.
     
  5. redsoxfan

    redsoxfan Senior Member
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    but wouldn't you want the little O2 you have to go to the tissues (ie less bound to Hb)?
     
  6. redsoxfan

    redsoxfan Senior Member
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    ok apparently there was an error on the answer key. it does shift right. thanks anyhow :)
     
  7. redsoxfan

    redsoxfan Senior Member
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    i stand corrected. it is to the left b/c of compensatory hyperventilation causing decr CO2. i apologize to anyone who tried to correct me before.
     
  8. kdburton

    kdburton Ulnar Deviant
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    Hemoglobin saturation of O2 goes down with less O2 partial pressure. So at higher altitude (with lower O2 partial pressure) the curve shifts to the left.
     
  9. Misfit!

    Misfit! Ihate everything aboutyou
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  10. BruceWayne

    BruceWayne Member
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    I remember being confused by that same question because I think I read in the bio review book that it would shift right (in chapter 8 i think). But a left shift makes more sense. :luck:
     

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