What does the bicarbonate buffer system regulate in the body?

• A. Respiratory rate
• B. Blood glucose levels
• C. Blood pH levels
• D. Body temperature

Answer: (C)

The bicarbonate buffer system is crucial for maintaining the pH levels in the blood, which is vital for proper physiological function. It operates by balancing the concentration of carbonic acid (H2CO3) and bicarbonate ions (HCO3-) in the bloodstream. When there is an increase in carbon dioxide (CO2) levels, it leads to the formation of more carbonic acid, which can dissociate into hydrogen ions (H+) and bicarbonate. This process helps neutralize excess acids, thus preventing significant fluctuations in blood pH.

Conversely, if the body fluids become too alkaline, the bicarbonate can donate a hydrogen ion to bring the pH back to the normal range. This dynamic equilibrium ensures that blood pH remains within a narrow range (approximately 7.35 to 7.45), which is essential for the optimal functioning of enzymes and the overall metabolic processes within the body.