What process refers to CO2 diffusing into the blood?

The process being described is CO2 loading, which specifically refers to the movement of carbon dioxide from the tissues into the blood. This occurs primarily in the capillaries surrounding tissues where cells produce CO2 as a byproduct of metabolism. During this process, CO2 diffuses down its concentration gradient into the red blood cells.

Once inside the red blood cells, a significant portion of the CO2 is converted into bicarbonate ions, which are then transported back to the lungs for exhalation. This mechanism is crucial for maintaining pH balance in the blood and ensures the continuous removal of CO2 from the body, which is vital for homeostasis.

In contrast, oxygen loading refers to the uptake of oxygen by hemoglobin in the blood, and respiratory exchange encompasses both oxygen loading and CO2 unloading in the lungs, neither of which specifically focuses on the diffusion of CO2 into the blood. Carbonic acid formation is a chemical reaction that occurs after CO2 is loaded into the blood and involves the conversion of CO2 and water into carbonic acid, facilitating the transport of CO2. Thus, CO2 loading is the most accurate term for the process in question.