Transport of O2 and CO2 in blood

Question 1

What dictates the relationship between the partial pressure of a gas and its concentration in solution?

Answer 1

Dalton’s law - for a given partial pressure, the higher the solubility of the gas, the higher the concentration of gas in solution

Question 2

How is metHb formed?

Answer 2

1. Oxidation of Fe2+ to Fe3+ by nitrites and sulfonamides 2. Deficiency of MetHb reductase

Question 3

Which subunits are abnormal in HbS?

Answer 3

Beta

Question 4

Does HbS have a higher or lower affinity for oxygen?

Answer 4

Lower

Question 5

What is the equation for oxygen content (actual amount of O2 per volume of blood)?

Answer 5

O2 content = O2 binding capacity x SaO2 + dissolved O2

Question 6

What is the equation for oxygen delivery to tissues?

Answer 6

O2 delivery = CO x oxygen content

Question 7

How does an increase in temperature affect the Hb binding curve?

Answer 7

Right shift - lesser affinity

Question 8

How does a decrease in plasma pH affect the Hb binding curve?

Answer 8

Right shift - lesser affinity

Question 9

How does an increase in plasma pCO2 affect the Hb binding curve?

Answer 9

Right shift - lesser affinity (lower pH)

Question 10

How does an increase in 2,3-BPG affect the Hb binding curve?

Answer 10

Right shift - lesser affinity

Question 11

Why is there no feedback mechanism for low O2 content during CO poisoning?

Answer 11

PaO2 is roughly normal

Question 12

How much CO2 in the blood is in the dissolved form?

Answer 12

7%

Question 13

How much CO2 in the blood is in conjugated form with Hb?

Answer 13

23%

Question 14

How much CO2 in the blood is in chemically modified HCO3- form in RBCs?

Answer 14

70%

Question 15

What is the Haldane effect?

Answer 15

1. Effect of O2 on CO2 equilibrium curve 2. Higher pO2 will shift CO2 equilibrium curve downward and to the right