Blood must be maintained at a fairly constant pH between 7.35 - 7.45. One of the principal buffers responsible for doing this consists of carbonic acid in equilibrium with bicarbonate ions. If you breathe too deeply or rapidly, a condition known as hyperventilation may occur in which some muscles are temporarily paralyzed because the pH of the blood becomes too high. Explain why the pH changes in this way and why the condition can be corrected by breathing in a paper bag.