Bicarbonate ions in the blood play a crucial role in maintaining physiological levels of what?

Bicarbonate ions in the blood are key players in the regulation of acid-base balance, which directly relates to the concentration of hydrogen ions. The bicarbonate buffering system is one of the body's primary mechanisms for maintaining blood pH within a narrow physiological range, typically around 7.35 to 7.45.

When there is an increase in hydrogen ions (H+) in the blood, such as during metabolic acidosis, bicarbonate ions (HCO3-) can react with these hydrogen ions to form carbonic acid (H2CO3), which can then dissociate into water (H2O) and carbon dioxide (CO2). This reaction effectively reduces the concentration of free hydrogen ions, helping to mitigate the decrease in pH. Conversely, if the pH is too high (alkalosis), the reaction can shift in the opposite direction, releasing hydrogen ions.

This ability to absorb or release hydrogen ions makes bicarbonate a vital component in maintaining homeostasis of hydrogen ion concentration, which is essential for many biological processes and enzyme activities that are sensitive to pH changes.