What is more critical to remove from venous blood, CO2 or O2 at the cellular level?

At the cellular level, the removal of carbon dioxide (CO2) is more critical than the removal of oxygen (O2). This is primarily because CO2 is a waste product of cellular respiration, a process that generates energy by breaking down glucose. Accumulation of CO2 can lead to a decrease in blood pH, resulting in acidosis, which can disrupt cellular functions and pose significant risks to overall metabolic homeostasis.

While oxygen is vital for the production of energy, it is generally present in more than sufficient quantities in the bloodstream, especially under normal physiological conditions. The body has mechanisms to transport and deliver oxygen efficiently to tissues; thus, a temporary decrease in O2 levels may not be as immediately harmful as an increase in CO2 levels.

Furthermore, CO2 removal is crucial for maintaining the acid-base balance and promoting effective gas exchange in the lungs. If CO2 is not promptly removed, it can cause respiratory issues and impact the body’s overall ability to function effectively. Therefore, the body prioritizes the clearance of CO2 from the bloodstream to maintain proper physiological conditions.