What is the primary compensatory mechanism for metabolic acidosis?

The primary compensatory mechanism for metabolic acidosis is hyperventilation. In this condition, the body experiences an increase in acidity, often due to an accumulation of acids (like lactic acid) or a loss of bicarbonate (such as in diarrhea). To counteract the acidic environment, the respiratory system responds by increasing the rate and depth of breathing, a process known as hyperventilation. This increases the expulsion of carbon dioxide (CO2) from the body.

When CO2 levels decrease through rapid breathing, it helps raise the blood pH back towards normal by reducing the concentration of carbonic acid formed when CO2 combines with water in the body. Thus, hyperventilation is an essential and immediate compensatory response aimed at restoring acid-base balance in cases of metabolic acidosis.

The other options, while relevant to various physiological responses, do not serve as the primary compensatory mechanisms in this context.