Blood gas transport Flashcards
Describe the pressure differences that cause oxygen to diffuse into the pulmonary capillary
PO2 in the alveolus is 104 and the Po2 entering the capillary is 40
104-40=64 mmHg
What factors allow the diffusion capacity of oxygen to increase during exercise?
Increased surface area of capillaries
more ideal V/Q ratio in the upper parts of the lungs
What is the normal range for the intracellular PO2?
5-40 mmHg mean of 23 mm Hg
What are the factors that determine tissue PO2?
Rate of oxygen transport to the tissues
Rate of oxygen consumption but the tissues
What is the PO2 at the arterial end of the capillary? At the venous end?
arterial end= 95 mmHg
venous end= 40 mmHg
What is a normal PCO2?
Arterial blood?
Venous blood?
Normal= 46 mmHg
Arterial= 40mmHg
Venous=45mmHg
Describe the numerical values that are involved in oxygen transport
- How many grams of Hb are in a dl of blood?
- How many ml of O2 can 1 g of Hb bind to?
- How many ml of O2 does 1 dl of blood carry?
- 15 g/dl blood
- 1 gran of Hb can bind to 1.34 ml O2
- 1 dl blood carries 20.1 ml O2
Describe the utilization coefficient and how to find it
Percentage of blood that gives up oxygen
5/19.4 = 25%
How is hemoglobin seen as a “tissue oxygen buffer” system?
When PO2 is high (pulmonary capillaries), oxygen binds with hemoglobin
When PO2 is low (tissue cap), oxygen is released from the hemoglobin
What happens to the pH when there is an increased pCO2?
It decreases the pH
What are the factors that will shift the oxygen-hemoglobin curve to the right?
- increased H+ ions (decreased pH)
- Increased CO2
- Increased temperature
- Increased BPG
What is the Bohr effect?
- increase in blood (CO2) and H+ ions
- shifts curve tot he right, enhances O2 release in the tissues and oxygenation of blood in the lungs - Decrease in blood CO2 and H+ ions
- shift of the curve to the LEFT
- happens in the lungs
What are the 3 ways in which CO2 can be transported in the blood?
- small amount dissolved in the blood
- 70% is transported by carbonic acid
- carbamino hemoglobin
Describe the Bohr effect in relation to the Haldane effect
The Bohr effect is an increase in CO2 which causes O2 to be released from the hemoglobin (shifts right)
the Haldane effect is the binding of O2 with hemoglobin which displaces CO2 from the blood (increases the acidity of the hemoglobin which causes the relase of hydrogen ions)
Describe what carbon monoxide does in the body
Why is the blood BRIGHT red?
displaces the oxygen on the hemoglobin molecule
binds to O2 250X stronger
Blood is bright red because the oxygen content of the blood is greatly reduced BUT the PO2 may be normal
