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How is the Haldane effect diff from the Bohr effect?

Discussion in 'MCAT Study Question Q&A' started by thebillsfan, 07.19.09.

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  1. thebillsfan

    thebillsfan Unseasoned Veteran 5+ Year Member

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    I looked them up on Wikipedia and they seem the same to me.
     
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  3. sv3

    sv3 2+ Year Member

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    not totally sure - i noticed Ek mentions Haldane but TPR doesn't. I thought Haldane had to do with CO2 and O2 while Bohr is centered around Hb's ability to bind O2 and CO2 is a more minor part.

    In the end, they are both highly related. Not sure I'd worry about it that much if you get both concepts.
     
  4. rocuronium

    rocuronium 7+ Year Member

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    The simplest way to differentiate the two effects is to identify which molecule is the cause of the change.

    The Haldane effect describes how oxygen concentrations determine hemoglobin's affinity for carbon dioxide. For example, high oxygen concentrations enhance the unloading of carbon dioxide. The converse is also true: low oxygen concentations promote loading of carbon dioxide onto hemoglobin. In both situations, it is oxygen that causes the change in carbon dioxide levels.

    The Bohr effect, on the other hand, describes how carbon dioxide and H+ affect the affinity of hemoglobin for oxygen. High CO2 and H+ concentrations cause decreases in affinity for oxygen, while low concentrations cause high affinity for oxygen.

    To further illustrate the difference, it might help to look at specific examples. In the lungs, when hemoglobin loaded with carbon dioxide is exposed to high oxygen levels, hemoglobin's affinity for carbon dioxide decreases. This is an example of the Haldane effect.

    In active muscles, carbon dioxide and H+ levels are high. Oxygenated blood that flows past is affected by these conditions, and the affinity of hemoglobin for oxygen is decreased, allowing oxygen to be transferred to the tissues. Because we are looking at the situation from the perpsective of carbon dioxide changing oxygen affinity, this is an example of the Bohr effect.

    I hope this has helped to clear up the confusion.
     
  5. sv3

    sv3 2+ Year Member

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    great explanation
     
  6. thebillsfan

    thebillsfan Unseasoned Veteran 5+ Year Member

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    thanks! haha so looks like two guys were trying to get credit for finding the same phenomenon. although they're worded differently, they're so interrelated that they really should be considered one effect IMHO
     
  7. Hemichordate

    Hemichordate Peds 7+ Year Member

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    I'm wondering about this:

    If the temperature is increased, the curve shifts to the right, and we breathe faster. But if temperature is decreased (i.e. thrown into a really cold pool), why do we still breathe faster? Shouldn't we be breathing slower?
     
  8. matth87

    matth87 2+ Year Member

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    Its called adrenaline (epinephrine and norepinephrine)
     
  9. rocuronium

    rocuronium 7+ Year Member

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    Are you directly relating the shift in the curve to the change in respiratory rate?

    If you were exposed to very cold water and could somehow mitigate the effects of the sympathetic nervous system, your respiratory rate would likely decrease. Understand, however, that although a left shift in the OHDC may be observed, it does not directly cause the change in respiratory rate. There are many other processes to consider, which may lead to confusion when attempting to predict a physiological response.
     
  10. Hemichordate

    Hemichordate Peds 7+ Year Member

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    Is the increase in respiration with a right shift simply due lowered affinity for oxygen (by hemoglobin)
     
  11. SuperSaiyan3

    SuperSaiyan3

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    possibly the best and clear explanation I've ever read in my life.

    This man deserves a nobel prize for this... or be granted a wish by the Shenlong from Dragonball Z
     
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  12. rocuronium

    rocuronium 7+ Year Member

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    The primary influence on respiratory rate is carbon dioxide levels.

    Respiratory rate changes, just like shifts in the curve, happen in response to changes in metabolism. Just as the higher carbon dioxide levels result in a right shift in the curve, they result in a chemoreceptor response which increases the respiratory rate.
     
  13. Ozziemedic

    Ozziemedic

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    Cheers Rocuronium,

    as said above, that was such a clear and exemplified explanation of the Haldane and Bohr Effects that I decided to join this community for when I have other questions. Maybe one day I'll come across an enquiry in which I'm learned enough to give back.

    Ozziemedic
     
  14. LillyCrystaline

    LillyCrystaline

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    Great great explanation, but i have a question, Do Haldane and Bohr have a "vice versa" option? I mean, Does Bohr effect only occur at tissues, and Haldane effect only occur at lungs?
     
  15. Mohammed Guba

    Mohammed Guba

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    At the lungs, where there is low CO2 and high O2, both haldane and bohr effect alike will make sure oxygen binds Hb while CO2 leaves Hb?
     
  16. jllb92

    jllb92

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    In the tissues, CO2 is converted by carbonic anhydrase to carbonic acid which spontaneously loses a proton, the binding of H+ to Hb stabilize the T (deoxy) form resulting in a decreased oxygen affinity of hemoglobin and, therefore, a shift to the right in the oxygen-dissociation curve, thus enhancing the release of O2 from Hb, thus when the RBC are in the lungs that have a higher pH, Hb has a higher affinity thus saturating itself with O2, but when the RBC get to the tissues the CO2 that diffuses from the tissues to the RBC forms HCO3-and H+ wich binds to Hb and reduces its affinity thus favoring the loading of oxygen in the tissues, this is called the Bohr effect.

    Deoxygenation of Hb leads to an increase affinity for CO2 wich allows to increase the Hb transport of CO2 , OxyHb has low affinity for CO2 so when the RBC gets to the lungs CO2 dissociates from Hb and can be eliminated by the lung, this is the Haldane effect.
     

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