What does the blood transport between the lungs and tissues?
What does blood transport between the tissues and the lungs?
What is the waste product of using oxygen to produce energy?
How much oxygen dissolves per litre of blood plasma?
How is the blood carrying capacity of oxygen increased?
Presence of haemoglobin
What does haemoglobin increase the oxygen carrying capacity of blood to?
How is CO2 transported in the plasma?
In various forms
What is arterial partial pressure of oxygen (PaO2) not the same as?
What does PaO2 refer to?
O2 in solution
What is PaO2 determined by?
O2 solubility and the partial pressure of O2, in the gaseous phase that is driving O2 into solution
How do values of partial pressure of gases in solution compare to the partial pressure in gaseous phase that is driving the gas into solution?
They are equal
What is O2 solubility in water?
If 3ml of oxygen is present per litre of plasma, what is the partial pressure that is driving O2 into the loquid phase in plasma?
This is because solubility of water is 0.03ml/L/mmHg (3/0.03 = 100)
What is the partial pressure of oxygen also known as?
How does PO2 in the liquid phase compare to that in the gaseous phase, and to the concentration in the liquid phase?
PO2 is the same in the liquid phase as the gas phase
PO2 in the liquid phase is different from the concentration as that varies depending on what phase the gas is in
How many molecules are there of oxygen in 1L of gas compared to 1L of liquid?
30x more oxygen molecules
How do you work out the O2 delivery to tissues?
Arterial O2 content x Cardiac output
3ml/L x 5L/min = 15ml/min
What percentage of arterial O2 is extracted by peripheral tissues at rest?
What does reduced PO2 result in for oxygen carrying capacity of red blood cells and plasma?
Decreases blood carrying capacity
What is the abbreviation of haemoglobin?
What percentage of oxygen in systemic arterial circulation is bound to haemoglobin?
More than 98%
How much oxygen does 1L of systemic arterial blood contain?
How does haemoglobin bind to oxygen?
Cooperatively binds to 4 molecules of oxygen
How much oxygen binds to each gram of haemoglobin?
What form is most haemoglobin in red blood cells in?
What does a haemoglobin molecule contain?
What are some forms of haemoglobin other than HbA?
HbA2 (δ chains replace β)
HbF (γ chains replace β)
Glycosylated Hb (HbA1a, HbA1b, HbA1c)
What is the major determinant for the degree to which haemoglobin is saturated with oxygen?
Partial pressure of oxygen in arterial blood
Why does the partial pressure of oxygen not change as haemoglobin binds to it?
It effectively hides it from the plasma, maintaining the partial pressure gradient that continues to suck O2 out of alveoli until Hb becomes saturated
What formula represents Hb binding to oxygen?
Hb + O2 ⇔ HbO2