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15 Cards in this Set

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What favors unloading of O2 in tissues
Since H+ concentration is high, temp is high, and HbCO2 concentration is high in tissues then there is a lowered affinity of Hb for O2 in tissues and unloading of O2 occurs and uptake of CO2 takes place
What happens to the affinity of Hb for 02 in the lungs
In the lungs, H+ is low, HbCO2 is low, these factors raise Hb affinity for O2 in the lung and unloading of CO2
What happens to O2/CO2 in the alveolar capillaries
PO2=100, O2 is loaded into blood. PCO2=40, CO2 is unloaded from the blood. H+ ion concentration is low, and temp. is low
What happens to O2/CO2 in the tissue capillaries
PO2=40, O2 is unloaded from blood. PCO2=46, CO2 is loaded into blood. H+ concentration is high, temp. is high
define cooperative effect between O2 and CO2
when one gas is removed from blood, it enhances the uptake of the other.
Give specific examples of the cooperative effect in the lungs
In lungs, the removal of CO2:

Promotes O2 uptake by lowering the H+ concentration, which raises the affinity of Hb for O2
Promotes O2 uptake by releasing H+ and CO2 bound to Hb, leaving the sites available for O2
How is the affinity of Hb regulated
Hb affinity is regulated by the organic phosphate molecule 2,3 DPG. The molecule is present is RBC in equal molar concentrations to Hb, and associates with Hb...lowering Hb affinity for O2
Why does the affinity of Hb for O2 need to be regulated
because Native Hb has a very high affinity for O2, in its native form Hb is incompatable with life
what is the P50 of Hb without 2,3 DPG
2 mmHg
What happens to affinity of Hb and 2,3 DPG with persistent hypoxia
persistent hypoxia (days to weeks) results in increases in 2,3 DPG, which lowers Hb affinity for O2
What can happen to 2,3 DPG levels in stored blood
DPG can be degraded in stored blood, as DPG levels drop, the affinity of Hb rises. Infusing a patient with blood containing Hb with very high affinity for O2 can be dangerous.
What is a second adaptation by the body to chronic hypoxemia
as a result of chronic hypoxemia, the body generates new RBC's following hypoxemia. Results is an increase in HCT and additional O2 carrying capacity of the blood. The downside is increased blood volume and increased viscocity of blood create additional workload on heart
How do we determine how well gases are being transported in the body
we need to look at how well we are maintaining an adequate PO2 in organs or tissues that are actively metabolizing
how is it possible to determine the PO2 in some solid organ or tissue
Use the PO2 in venous blood from a metabolizing organ or tissue as an estimate of the PO2 inside the organ
On average how much less vol% does venous blood have compared to arterial blood
5 vol% less