Regarding carbon monoxide poisoning

Discussion in 'NBDE Exams & Licensure Exams' started by acrylic, Jun 20, 2008.

  1. acrylic

    acrylic New Member

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    which of the following is NOT charcterstic of carbon monoxide poisoning?

    A. Decreased arterial partail pressure of oxygen.

    B. Increased affinity for Hb.

    C. no change in alveolar ventilation.

    D.decreased arterial Oxygen concentration.

    E. Shifting of oxy hemoglobin curve to left.


    answer is D plz explain how


    Q..how many nadh are produced in one turn of kreb's cycle starting with 2 molecules of pyruvate
    i thought 6 but answer is 8....
     
    #1 acrylic, Jun 20, 2008
    Last edited: Jun 20, 2008
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  3. Discovery01

    Discovery01 Member

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    I found a source that had a similiar question, but other answer.

    Features of mild carbon monoxide poisoning include:





    A: decreased arterial PO2.


    B: decreased hemoglobin-oxygen affinity.


    C: increased alveolar ventilation.


    D: decreased arterial O2 concentration.


    E: all of the above.

    The answer is D. - decreased arterial O2 concentration.

    Carbon monoxide poisoning causes some of the hemoglobin in the blood to be combined with CO to give carboxyhemoglobin. As a result, there is a decreased arterial O2 concentration (choice D is correct). However, it is important to realize that this does not decrease the arterial PO2. In this respect, carbon monoxide poisoning is similar to anemia where again the arterial PO2 is typically normal but the arterial oxygen concentration is reduced.

    Choice B is not correct. There is an increase in the affinity of the hemoglobin for oxygen as evidenced by the leftward shift of the oxygen dissociation curve. Thus, carbon monoxide poisoning causes a fall in tissue PO2 for two reasons: first less oxygen is carried in the arterial blood, and second the unloading is impeded by the higher hemoglobin affinity.

    Choice C is incorrect. Ventilation is unaffected in mild carbon monoxide poisoning; the chemoreceptors respond primarily to the arterial PO2 and, because this is normal, ventilation remains essentially unchanged.

    The word “mild” is included in the stem of the question because with very severe carbon monoxide poisoning there may be brain damage which may alter ventilation.

    http://www.mountain-research.org/teaching/pulmonary.htm#answer12
     
  4. acrylic

    acrylic New Member

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    i get ur point but the ques i potsed asks wich of the following is not a feature of co poisioning,and then it says decreased arterial O2 n acc to ur exp it should be be dec partial pressure coz that remains normal inco poisioning
     
  5. dreamdental

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    could you please explain..
    ventillation is nothing but exachange of oxygen/co2 between alveoli and blood.If oxygen is not taken becuase CO-Hb ,then ventillation should be decreased.what you said is correct but what about this point..
     
  6. acrylic

    acrylic New Member

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    hi
    ventilation is nothing but the amount of air entering in the lungs,in co poisioning it will not be affected coz co does not stop ne air entering the lungs....hope it helps
     
  7. dreamdental

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    i think you dint understand my point .oxygen does not go in to blood as Hb is occupied by CO so there will less amount of oxygen goin inn so the ventillationh
     
  8. Streetwolf

    Streetwolf Ultra Senior Member
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    Tricky because of the wording. Though it says Krebs cycle, it also says 'starting with 2 molecules of pyruvate'. Don't forget that pyruvate decarboxylation leads to 1 NADH per molecule of pyruvate. That accounts for your missing 2 NADH molecules.
     
  9. acrylic

    acrylic New Member

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    thks
     
  10. porcelain258

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    alv. ventilation is simply the exchange of gases across the alveolar membranes OR the amt of gas moving in and out of lungs
    nothing to do with the binding of o2 with the hemoglobin:thumbup:
     
  11. SM156

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    CO poisoning causes the carotid body to sense low oxygen content in the blood.. This causes CN-9 to signal the respiratory center in the medulla to increase cardiac and respiratory rate
     

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