The kidneys compensate for respiratory alkalosis by (excretion, retention) of bicarbonate and (increased, decreased) excretion of NaH2PO4.

The kidneys compensate for respiratory alkalosis by (excretion, retention) of bicarbonate and (increased, decreased) excretion of NaH2PO4.

• A. Excretion, decreased
• B. Excretion, increased
• C. Retention, increased
• D. Retention, decreased

Answer: (B)

When respiratory alkalosis occurs, CO2 is reduced and the blood becomes more alkaline. The kidneys respond by lowering the bicarbonate level in the blood to counteract the alkalosis. This happens because more bicarbonate is excreted in the urine, decreasing plasma HCO3-. At the same time, the kidneys increase excretion of acid, mainly by forming and eliminating titratable acid with phosphate as NaH2PO4. This combined action—losing bicarbonate and increasing acid excretion—moves the pH back toward normal. Retaining bicarbonate or not increasing acid excretion would worsen or fail to correct the alkalosis, so the correct pattern is excretion of bicarbonate with increased excretion of NaH2PO4.

When respiratory alkalosis occurs, CO2 is reduced and the blood becomes more alkaline. The kidneys respond by lowering the bicarbonate level in the blood to counteract the alkalosis. This happens because more bicarbonate is excreted in the urine, decreasing plasma HCO3-. At the same time, the kidneys increase excretion of acid, mainly by forming and eliminating titratable acid with phosphate as NaH2PO4. This combined action—losing bicarbonate and increasing acid excretion—moves the pH back toward normal. Retaining bicarbonate or not increasing acid excretion would worsen or fail to correct the alkalosis, so the correct pattern is excretion of bicarbonate with increased excretion of NaH2PO4.