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37 terms

Module II: UNIT 6, Lesson 3

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Assuming all conditions for gas exchange are ideal, and the O2 enters the blood through the respiratory membrane, what 3 factors determine how much O2 will be transported in the blood from the lungs to the tissues?
1) Pa O2 in blood
2) Quantitly of hemoglobin per 100 ml of blood
3) The chemical environment in the blood
What is the Pa O2 and the Pa CO2 of inspired air before it reaches the alveoli?
Pa O2 = 160 mmHg
Pa CO2 = 0.3 mmHg
What is the Pa O2 and the Pa CO2 at the alveoli in the lungs?
Pa O2 = 104 mmHg
Pa CO2 = 40 mmHg
What is the pa O2 and Pa CO2 in the blood leaving the alveolar capillaries?
Pa O2 = 104 mmHg
Pa CO2 = 40 mmHg
What is the Pa O2 and Pa CO2 in the blood of the pulmonary veins?
Pa O2 = 95 mmHg
Pa CO2 = 40 mmHg
What is the Pa O2 and Pa CO2 in the blood of the systemic arteries?
Pa O2 = 95 mmHg
Pa CO2 = 40 mmHg
What is the Pa O2 and Pa CO2 in the tissues of the body?
Pa O2= <40 mmHg
Pa CO2 = >45 mmHg
What is the Pa O2 and Pa CO2 in the blood leaving the tissue capillaries?
Pa O2 = 40 mmHg
Pa CO2 = 45 mmHg
What is the Pa O2 and Pa CO2 in the blood entering the avleolar capillaries on the way back to the lungs?
Pa O2 = 40 mmHg
Pa CO2 = 45 mmHg
What is the Pa O2 and Pa CO2 in expired air?
Pa O2 = 120 mmHg
Pa CO2 = 27 mmHg
Through what two mediums is O2 carried in the blood?
1) hemoglobin (97% of O2)
2) dissolved in plasma water
What is the formula used to determine the amount of O2 dissolved in the blood plasma?
O2 = Ks + PaO2
What does Ks stand for in the formula O2=Ks+PaO2?
Ks = solubility coefficient

*For O2 it is 0.003 ml O2 per dl mmHg
What would be the % of O2 dissolved in blood plasma if the Pa O2 = 125 mmHg? 130 mmHg?
%O2 = (0.003 x 125)/100 ml blood = 0.375 %
%O2 = (0.003 x 130)/100 ml blood = 0.390 %
How much O2/min is needed by the tissues to function at rest?
250 ml/min
TRUE or FALSE: O2 carried to the tissues by transportation in blood plasma is enough to supply the tissues at rest.
FALSE
What 2 physiological features of hemoglobin are important in the amount of O2 it can transfer?
1) quantity of hemoglobin
2) O2 affinity (amount of binding sites available)
On average, how many grams of hemoglobin are in 100 ml of blood?
15 grams
On average, how many ml of O2 are carried by 1 gram of hemoglobin?
1.36 ml O2
Determine the amount of O2 carried per 100 ml of blood.
(15 g hemoglobin/100 ml blood) x
(1.36 ml O2/1 g hemoglobin) = 20 ml O2/ 100 ml blood
What is the term used to describe the amount of O2 carried by hemoglobin present in a known quantity of blood?
oxygen carrying capacity
What is the term used to describe the amount of O2 carried by hemoglobin at any time?
content
Will a condition of polycythemia increase or decrease the O2 carrying capacity of hemoglobin?
increase
Will a condition of anemia increase or decrease the O2 carrying capacity of hemoglobin?
decrease
How many O2 binding sits does each molecule of hemoglobin contain?
4
What 2 factors determine the filling of the O2 binding sites on hemoglobin?
1) Pa O2
2) affinity of the binding sites to O2
What 4 factors affect the affinity of hemoglobin to O2?
1) pH of blood
2) blood CO2 levels
3) blood temperature
4) the level of diphospoglycerate (DPG)
Will an increase in hydrogen ion concentration increase or decrease hemoglobin's affinity to O2?
increase
TRUE or FALSE: A decrease in blood CO2 levels will correspond to an increase in hemoglobin's affinity to O2.
TRUE
Will an increase in blood temperate increase or decrease hemoglobin's affinity to O2?
decrease
Will an increase in DPG increase or decrease hemoglobin's affinty to O2?
decrease
Where is DPG produced in the body?
metabolizing tissues
TRUE or FALSE: A decrease in Pa O2 will cause a decrease in the % saturation of hemoglobin.
FALSE
What is used to measure the affinity of the binding sites on hemoglobin for O2?
P50
Define P50.
The partial pressure of O2 in the blood that brings about 50% saturation of hemoglobin.
Describe the Bohr Effect.
Following the release of CO2 into the lungs in the lung capillaries, blood CO2 levels decrease. This increases the affinity of hemoglobin to O2 and enhances O2 loading. In the tissue capillaries, the release of CO2 into the blood causes the bound O2 to be displaced from hemoglobin and taken up by the tissues.
Would the presence of carbonmonoxide affect hemoglobin affinity to O2?
Yes; Hemoglobin has higher affinity for carbonmonoxide and thus no O2 can bind to hemoglobin in the presence of carbonmonoxide.