Buffer Systems

A buffer absorbs excess acid or base, so the pH barely moves. Your blood relies on the carbonic acid-bicarbonate buffer, which mops up extra H+ or OH- ions and prevents swings that would denature proteins.

If blood pH drops below 7.0 or rises above 7.8, enzymes stop working and death can follow within minutes. Your body fine-tunes this constantly: breathing faster or slower changes CO2 levels, which shifts blood pH through carbonic acid.