Bikarbonatbufferten

Bikarbonatbufferten, also known as the bicarbonate buffer system, is a crucial physiological buffer found in the blood and extracellular fluid of vertebrates. It is composed of carbonic acid (H2CO3) and its conjugate base, bicarbonate ion (HCO3-). This system plays a vital role in maintaining the pH of the blood within a narrow physiological range, typically between 7.35 and 7.45.

The bicarbonate buffer system works by reversibly reacting with acids and bases. When the body produces an excess of acid, such as lactic acid during strenuous exercise, the bicarbonate ions react with these hydrogen ions to form carbonic acid. Carbonic acid is a weak acid that can then be converted into carbon dioxide (CO2) and water (H2O). The CO2 is then expelled from the body through respiration. Conversely, if the body becomes too alkaline, the carbonic acid can donate hydrogen ions to neutralize the excess base.

The balance of the bicarbonate buffer system is tightly regulated by both the respiratory and renal systems. The lungs control the elimination of CO2, thereby influencing the concentration of carbonic acid. The kidneys, on the other hand, can reabsorb or excrete bicarbonate ions, allowing for long-term pH adjustments. This integrated control mechanism ensures that blood pH remains stable, which is essential for the proper functioning of enzymes and other cellular processes. Disruptions to the bicarbonate buffer system can lead to acid-base imbalances like acidosis or alkalosis.