What is considered the most important buffer of hydrogen ions in the body?

Bicarbonate is considered the most important buffer of hydrogen ions in the body due to its key role in maintaining acid-base balance. It acts as a primary component of the body's buffering system, specifically in the extracellular fluid. Bicarbonate ions can quickly react with excess hydrogen ions ( H+) to form carbonic acid, thus preventing significant changes in pH levels.

In the bicarbonate buffering system, when the pH of the blood drops (indicating an increase in acidity), bicarbonate can neutralize excess hydrogen ions, minimizing the potential for acidosis. Conversely, if the pH rises (indicating alkalinity), carbonic acid can dissociate to release hydrogen ions, helping to stabilize the pH. This dynamic balance is essential for normal physiological functions, as most enzymatic and biochemical processes in the body operate optimally within a narrow pH range.

While carbonic acid, phosphate, and proteins also participate in buffering mechanisms within the body, their roles are not as prominent as that of bicarbonate in the regulation of extracellular pH, especially in the context of respiratory and metabolic acidosis and alkalosis.