Why is the bicarbonate buffer system referred to as a physiological buffer?

Question

Why is the bicarbonate buffer system referred to as a physiological buffer?

Answer 1

The previous answer does not correctly describe a buffering system.

A buffering system is defined as one that resists a change in pH, principally by its ability to negate changes in H+ (acid) or OH- (base) ions. The bicarbonate system functions as a buffer within the body by shifting its equilibrium toward carbonic acid (H2CO3) or bicarbonate (HCO3-) in order to maintain physiological pH between 7.35 and 7.45. In shifting equilibrium, H+ ions may either be absorbed or released from/into the blood, and thus it fits the definition of a chemical buffer

The reason it is called a physiological buffer is because pH-level affects function of enzymes within the body, and the level is optimally kept around 7.4 in order to preserve efficient enzymatic function. "Physiological" generally just refers to the function of an organism, whether it be physical, biochemical, or otherwise.

Answer 2

One mechanism the body uses to control blood pH involves the release of carbon dioxide from the lungs. Carbon dioxide, which is mildly acidic, is a waste product of the metabolism of oxygen and, as such, is constantly produced by cells. As with all waste products, carbon dioxide gets excreted into the blood. The blood carries carbon dioxide to the lungs, where it is exhaled. As carbon dioxide accumulates in the blood, the pH of the blood decreases. The brain regulates the amount of carbon dioxide that is exhaled by controlling the speed and depth of breathing. The amount of carbon dioxide exhaled, and consequently the pH of the blood, increases as breathing becomes faster and deeper. By adjusting the speed and depth of breathing, the brain and lungs are able to regulate the blood pH every minute

The kidneys are also able to affect blood pH by excreting excess acids or bases. The kidneys have some ability to alter the amount of acid or base that is excreted, but because the kidneys make these adjustments very slowly than the lungs do, this compensation generally takes several days.
As acid base balance is needed to be maintained constantly and lungs play the vital role through bicarbonate buffering , it`s called physiological.