Blood Gas Transport Flashcards
In the pulmonary capillary, the blood PO2 rises close to that in the alveolar air by the time the blood has moved _____ the distance through the capillary.
1/3
What factors allow the diffusion capacity of oxygen to increase during exercise?
Increased surface area of capillaries participating in diffusion.
Ideal Va/Q ratio in the upper parts of the lungs
What factors determine tissue PO2?
Rate of oxygen transport to the tissues
Rate of oxygen consumption by the tissues
Describe the effects of blood flow and metabolic rate on peripheral tissue PCO2.
As blood flow increases, interstitial fluid PCO2 decreases.
As metabolism increases, interstitial fluid PCO2 increases.
What is the oxygen saturation in venous blood and arterial blood?
Venous blood = 75%
Arterial Blood = 97%
How much oxygen is bound to heme groups in venous blood?
Oxygen is bound to approximately 3/4 (75%) of heme groups in blood.
How much oxygen is bound to heme groups in arterial blood?
Almost all of it (97%)
How is the oxygen utilization coefficient calculated?
It is the percentage of blood that gives up its oxygen.
5/19.4 ml O2 = 25% at rest
Strenous exercise = 75 to 85%
How can hemoglobin be viewed as a tissue oxygen buffer system?
Tissue PO2 does not rise above 40 mm Hg, and PO2 must fall to about 40 mm Hg to release 5 mL of blood.
When PO2 is high (pulmonary capillaries), oxygen binds with hemoglobin.
When PO2 is low (tissue capillaries), oxygen is released from hemoglobin.
Relate PO2 and oxygen saturation to the oxygen-hemoglobin dissociation curve.
As pressure oxygen in blood increases, hemoglobin saturation increases.
At 95 mm Hg, oxygenated blood leaves the lungs.
At 40 mm Hg, reduced blood returns from tissues.
Relate PO2 to quantity of bound oxygen per unit of blood.
As PO2 increases, there is a higher amount of of bound oxygen per unit of blood.
Relate pH to oxygen-hemoglobin dissociation curve
Decreased pH shifts the curve to the right.
This enchnces release of oxygen from the blood in the tissues and enhances oxygenation of blood in the lungs.
Increased pH shifts the curve to the left. This occurs in the lungs.
What is the Bohr effect, and what effect does it have on the oxygen-dissociation curve?
It shows the effect of pH on oxygen-hemoglobin curve. As pH decreases, the curve shifts to the right. As pH increases, the curve shifts to the right.
What occurs when blood pH decreases?
The oxygen-hemoglobin curve shifts to the right
Oxygen is released more readily from blood in the tissues.
Oxygenation of blood in the lungs occurs.
What occurs as pH increases?
The oxygen-hemoglobin curve shifts to the left.
This occurs in the lungs.
