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  #1  
Old 06-21-2014
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Default respi physio

Oxygen unloading is increased when hemoglobin passes through active tissues. Which of the following is one reason for this phenomenon?


A. Decreased temperature in the peripheral tissues shifts the hemoglobin dissociation curve to the left
B. Increased temperature in the active tissues shifts the hemoglobin dissociation curve to the left.
C.Increased CO2 and H+ in the peripheral tissues shift the hemoglobin dissociation curve to the right
D.Increased CO2 and H+ shift the hemoglobin dissociation curve to the leftE.Increased CO2 and increased diphosphoglycerate shift the hemoglobin dissociation curve to the left
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  #2  
Old 06-22-2014
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I thinks its C
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Old 06-22-2014
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Quote:
Originally Posted by dr_pawandeep View Post
Oxygen unloading is increased when hemoglobin passes through active tissues. Which of the following is one reason for this phenomenon?


A. Decreased temperature in the peripheral tissues shifts the hemoglobin dissociation curve to the left
B. Increased temperature in the active tissues shifts the hemoglobin dissociation curve to the left.
C.Increased CO2 and H+ in the peripheral tissues shift the hemoglobin dissociation curve to the right
D.Increased CO2 and H+ shift the hemoglobin dissociation curve to the leftE.Increased CO2 and increased diphosphoglycerate shift the hemoglobin dissociation curve to the left
answer is C.
right side shift of OD curve means decreased affinity of Hb to O2 and more O2 unloaded to tissues.
increased H+ (metabolic acidosis low pH)
increased CO2 hypercapnia
increased temperature hyperthermia
increased 2,3-BPG
High altitude
exercise
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Old 06-22-2014
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THE SOURCE IS USMLERX
The correct answer is A. Temperatures are increased, not decreased, in active tissues and serve to shift the hemoglobin dissociation curve to the right to facilitate oxygen unloading

i also opted for C and here is what they expalined for it
Active tissues produce acid, CO2, higher temperatures, and diphosphoglycerate (DPG). Each of these shifts the hemoglobin dissociation curve to the right, facilitating oxygen unloading. A shift of the curve to the right means that at the same partial pressure ofoxygen (PO2), the percent saturation of hemoglobin is lower. A shift to the left means that at the same PO2, the percentsaturation of hemoglobin is higher, or hemoglobin affinity for oxygen is higher. A shift to the left occurs with low CO2, low DPG, low temperature, and alkaline pH. A useful mnemonic is CADET, face right!: CO2, Acid (or low pH), DPG, Exercise, and Temperature shift the curve to the RIGHT
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Old 06-22-2014
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Answer A doesn't make sense to me.. It should be C.. I got same type of question on uworld ..
May be there is some mistake
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Old 06-22-2014
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Quote:
Originally Posted by dr.ann View Post
answer a doesn't make sense to me.. It should be c.. I got same type of question on uworld ..
May be there is some mistake
yeah and i cant make sense of the explanation they provide
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