04.2 Carbon Dioxide in the Blood

Question 1

What is the normal ratio of HCO3 to CO2?

Answer 1

20:1

Question 2

What happens in venous blood due to the drop in O2?

Answer 2

More H+ can bind to Hb
This allows more HCO3 to form and be exported to plasma
This buffers the increases CO2 in the plasma due to metabolism in tissues

Question 3

What happens at the lungs in response to O2 being picked up by Hb?

Answer 3

H+ is removed.

H+ reacts with HCO3- which forms CO2 which is then breathed out.

Question 4

What are the three main forms which CO2 is transported?

Answer 4

Dissolved in plasma
As hydrogen carbonate
Carbamino compounds (amino groups on globin)