Clinical Correlates of pH Levels
Problem Set

Problem 4: Additional rapid response to acidosis

Correct!

Continuing with the previous question, an additional rapid response to metabolic acidosis kicks in at or below pH 7.14, which is:

A.	retention of OH- in the kidney. Even if this did happen, it would be very slow and incomplete compared to the real response, which is instantaneous.
B.	retaining HCO3- in the kidney. Although this does help a little, it is too slow and incomplete to do much good.
C.	excreting H+ in the kidney. This might help a little, but is very slow and incomplete.
D.	direct buffering action of the H2CO3 central intermediate. In tissues at pH values below 7.14 (i.e., within one pH unit of the pKa), H+ ions are instantaneously absorbed by bicarbonate ion.
E.	retaining CO2 in the lung. This would actually make the situation worse.