How does the body primarily compensate for metabolic acidosis?

In metabolic acidosis, the body responds primarily through respiratory compensation by increasing ventilation, which is referred to as hyperventilation. This physiological response aims to decrease the level of carbon dioxide (CO₂) in the blood. As CO₂ combines with water in the body, it forms carbonic acid; therefore, by exhaling more CO₂, the body helps to reduce the acidity of the blood, effectively helping to raise the pH back towards normal levels.

While it is true that the kidneys also play a vital role in compensating for metabolic acidosis through various mechanisms, such as increasing the reabsorption of bicarbonate and excreting hydrogen ions, the immediate response to an acidotic state is usually through the lungs. Hyperventilation occurs quickly compared to the renal response, which can take hours to days to adapt properly.

The other options do not accurately describe the primary compensation mechanism in metabolic acidosis. For instance, increased excretion of bicarbonate is not a compensatory mechanism; rather, bicarbonate levels typically decrease in metabolic acidosis. Kidney retention of chloride is also not a direct compensatory mechanism in response to acidosis, and inhibition of alveolar function would generally worsen the state of acidosis rather than compensate for it.