Manitoba Nephrology Nurse Practice Test

What does the kidneys do to manage high pH?

1. Increase absorption of sodium

2. Decrease absorption of hydrogen ions

3. Increase excretion of bicarbonate

4. Decrease urine concentration

The correct answer is: Increase excretion of bicarbonate

The kidneys play a crucial role in maintaining acid-base balance in the body, including managing blood pH levels. When the body experiences a high pH, which indicates a more alkaline state or potential alkalosis, the kidneys respond by regulating bicarbonate levels. Specifically, increasing the excretion of bicarbonate is an appropriate response. Bicarbonate is a key buffer in the blood, and by excreting more of it into the urine, the kidneys help to decrease its concentration in the blood. This action effectively lowers the blood pH back towards the normal range, helping to counteract the alkaline state. In contrast, other mechanisms such as increasing the absorption of sodium or decreasing the absorption of hydrogen ions would not directly address high pH scenarios effectively, as they do not fundamentally alter bicarbonate levels in a way that would mitigate alkalosis. Additionally, decreasing urine concentration does not relate to pH management directly. Therefore, increasing the excretion of bicarbonate is the most effective means for the kidneys to manage a high pH situation.