Gas Transport Flashcards
What are the mechanisms for O2 transport in the blood?
- Dissolved
- Hemoglobin-bound
How much of the O2 does dissolved O2 make up?
0.3 mL/100 mL blood
This amount is essentially negligible.
What is Henry’s Law of gas solubility?
The concentration of a solute gas is proportional to is partial pressure above the solution.
What is the color of oxygenated Hb?
Red
What is the color of deoxygenated Hb?
Bluish
What is the significance of the O2 dissociation curve?
Its S-shaped slope facilitates the uptake of O2 at high pressures and the release at lower pressures
What is the normal P50 of O2?
27 mmHg - this is the partial pressure where Hb reaches 50% saturation
What happens with a right shift of the O2 dissociation curve?
It decreases the affinity of Hb for O2 and increases the P50 as a result.
What happens with a left shift of the O2 dissociation curve?
It increases the affinity of Hb for O2 and decreases the P50 as a result.
What happens to the O2 dissociation curve with exercise?
The curve will shift to the right and affinity for O2 will decrease due to increases in temperature, PCO2, 2,3-DPG and [H+]
What is the Bohr Effect?
Hb’s O2 binding affinity is inversely proportional to the acidity and CO2 concentration.
What occurs to the O2 dissociation curve in the presence of CO?
O2 curve will shift left and the O2 binding affinity of Hb will be greatly increased which will interfere with the unloading of O2.
What do victims of CO poisoning generally present with?
They are generally red due to O2 still being in the blood but it is just that it cannot be unloaded normally.
Where does hypoxemia become very dangerous?
Around 90% as the PO2 drops down to 60 mmHg
What is the normal O2 content in the venous blood?
75% saturation