What happens to pH during respiratory alkalosis?

What happens to pH during respiratory alkalosis?

• A. pH decreases.
• B. pH remains neutral.
• C. pH increases due to excessive CO2 exhalation.
• D. pH increases due to lactic acid buildup.

Answer: (C)

Excessive ventilation lowers carbon dioxide in the blood. CO2, when dissolved, forms carbonic acid that dissociates into hydrogen ions and bicarbonate. With CO2 being blown off too quickly, the carbonic acid concentration drops, hydrogen ion concentration falls, and the pH rises, making the blood more alkaline. This is why pH increases in respiratory alkalosis. It isn’t neutral, and it isn’t caused by lactic acid buildup (that would lower pH); the immediate change is the loss of CO2 leading to a higher pH.

Excessive ventilation lowers carbon dioxide in the blood. CO2, when dissolved, forms carbonic acid that dissociates into hydrogen ions and bicarbonate. With CO2 being blown off too quickly, the carbonic acid concentration drops, hydrogen ion concentration falls, and the pH rises, making the blood more alkaline. This is why pH increases in respiratory alkalosis. It isn’t neutral, and it isn’t caused by lactic acid buildup (that would lower pH); the immediate change is the loss of CO2 leading to a higher pH.