If you came to this series of posts hoping to find a rigorous theological debate regarding the existence of an omnipotent power...I'm sorry to disappoint (not really).
Carbon dioxide (CO2) is a metabolic byproduct of aerobic metabolism. Aerobic metabolism is our bodies' primary method of energy generation and it produces a large amount of CO2. This CO2 is released from our bodies into the external environment through our lungs, which will be discussed in a later post. This means that our blood has to transport CO2 from our tissues (e.g. your calf muscle) to our lungs.
There are 3 methods of CO2 transport:
1) CO2, like oxygen, is transported as a dissolved gas in blood plasma. This accounts for 2-10% of our blood's total CO2.
2) CO2 can bind to hemoglobin (and other blood proteins) and be transported to the lungs with the hemoglobin. A single CO2 binds to a single hemoglobin molecule (remember this is different than oxygen, 4 oxygen molecules bind to 1 hemoglobin molecule). This accounts for 5-10% of our blood's total CO2.
3) CO2 can be converted to bicarbonate (HCO3-) by an enzyme called carbonic anyhdrase. The chemical equation for this reaction is: CO2 + H20 -> H2CO3 -> H+ + HCO3-. This reaction is reversible. 80-90% of our blood's CO2 is transported as bicarbonate.
Note: An important concept to understand for future posts will be Le Chatelier's principle
, with regards to concentration, and how it applies to the above equation.
The next post will discuss how gas is exchanged in the lungs.