How do the kidneys compensate for alkalosis?

The kidneys play a crucial role in maintaining the body's acid-base balance. In the case of alkalosis, which is characterized by an elevated pH due to a decrease in hydrogen ion concentration, the kidneys respond by adjusting the excretion and retention of certain ions to help restore balance.

When the body is in a state of alkalosis, the kidneys will tend to retain hydrogen ions (H+) and excrete bicarbonate (HCO3-). This response helps to decrease the pH level back toward normal by increasing the acidity of the blood. By retaining hydrogen ions, the kidneys facilitate a compensatory mechanism that counteracts the alkalotic state. This adjustment helps to preserve the appropriate acid-base equilibrium.

In contrast, retaining bicarbonate or increasing kidney blood flow would not effectively correct a state of alkalosis and could exacerbate the condition, while retaining sodium and excreting potassium does not directly address the primary issue of elevated pH. Thus, the correct mechanism of kidney compensation for alkalosis is the retention of hydrogen ions and the excretion of bicarbonate.