Blood Gas Transport Flashcards
What are the different ways that oxygen is carried in the blood?
- Dissolved
2. Combined with hemoglobin
What would the cardiac output have to be in order to solely rely on dissolved O2?
83L/min
Max exercise is only 25-35- L/min
What is the structure of hemoglobin?
- Heme- with ferrous ion bound
- Globin- 2 alpha and 2 beta chains
How many O2 molecules can bind to one hemoglobin?
4
What influences the binding affinity of O2 to hemoglobin?
Already bound O2
What is methemoglobin?
This is when the ferrous ion has been converted to the ferric form by drugs or disease. Does not carry O2 very well
What is the O2 dissociation curve?
It shows the relationship between the O2 and amount of HbO2
What is the typical amount of O2 that Hb can carry?
1.34ml O2/g
What is the average concentration of Hb in the blood?
15g Hb/100ml
What is typical arterial O2 blood saturation level?
97%
What is the typical venous blood O2 saturation level?
75%
What is the total amount of O2 in the blood?
19.8 ml O2/ 100ml
What is the level of O2 extraction at rest?
25%
What is the amount of O2 in venous blood?
15ml O2/ 100ml
What is the extra oxygen in venous blood for?
Serves as an extra store of O2 during exercise. It is also why acute HF doesn’t see a large drop of O2 levels
What is P50?
This is the PO2 at which 50% of Hb is saturated and can tell us where the rest of the curve will lay
What is normal human P50?
27mmHg
What can cause P50 to be shifted to the right?
- Exercise= increase temp., lower pH, increase PCO2
- DPG
What is the consequence of moving P50 to the right?
It lowers the affinity so offload of O2 is faster
What is myoglobin?
This is found in high amount in highly oxidative muscles. It give them their red color. Assists in intracellular of O2. it shifts the O2 dissociation curve to the left
How is Carbon dioxide transported?
- Bicarbonate
- With proteins
- Dissolved
How is CO2 transported as bicarb?
Carbonic hydrogenase converts CO2 into HCO3- and H+. It travels through the blood like this until it gets to the lungs where it is converted back to CO2 and expired
What is Haldane’s effect?
HCO3- made in RBC can easily diffuse out but the H+ stays in. To keep electroneutrality, Cl- and water come in. H+ binds to hemoglobin and increase O2 offload and increases ability to carry CO2
What are carbamino compounds?
This is when CO2 binds to an amine group usually globin
What gas can you find at a higher dissolved concentration in the blood?
CO2
What type of Hb carries the most CO2?
Deoxygenated Hb
What is the difference in the Co2 and O2 dissociation curve?
Co2 is much more steep and linear
