CO2 in the Blood Flashcards
In arterial blood how much CO2 is there compared to O2?
2.5 x as much CO2
Why is there so much CO2 in the blood?
It acts as a buffer for pH
What range must the arterial blood pH be between?
7.35-7.45
What is the solubility coefficient for CO2 at 37 degrees C?
0.23
What happens to CO2 when it dissolves in the plasma?
It reacts with water to form carbonic acid, then H+ ions and hydrogen carbonate
What will happen to the plasma pH is pCO2 rises and falls?
rises = pH fall, falls = pH rises
What controls the pCO2?
Rate of breathing
What is the ratio of HCO3- to CO2?
20 x as much HCO3-
What causes the reaction of CO2 with H20 to proceed in the forwards direction?
H+ ions are bound to haemoglobin and HCO3- is removed from the RBC
What organ controls the concentration of HCO3-?
Kidney regulates its excretion
Why is pCO2 higher in venous blood?
It is coming from metabolically active tissues as a waste product
How is CO2 given up at the lungs?
Hb goes into R state, binding oxygen. H+ is released pushing equation in the backwards direction forming lots of CO2 which is then breathed out
What ways can CO2 travel in the blood?
Bound to the amine of Hb (carbamino compound), dissolved in plasma or as hydrogen carbonate
Roughly what is the percentage of pCO2 transported by the blood?
8%
What form is the majority of CO2 transported as?
60% Hydrogen carbonate
