The Urinary System Helps to Maintain the Extracellular Fluid PH

Question

The urinary system helps to maintain the extracellular fluid pH by ____.  
A) synthesizing buffers
B) retaining carbon dioxide in the filtrate
C) excreting excess hydrogen ions
D) combining hydrogen ions with urea
E) excreting filtrate

Accepted Answer

The urinary system helps to maintain the extracellular fluid pH by excreting excess hydrogen ions, which allows for the pH to become less acidic. This is done through the process of reabsorption, where hydrogen ions are secreted into the proximal tubules and then combined with bicarbonate ions to form carbonic acid. The carbonic acid then dissociates into water and carbon dioxide, which can be excreted as waste. This helps to keep the pH balance in the body.