How do the circulatory, excretory and respiratory systems work together to maintain pH homeostasis?

The pH balance is regulated mostly by the kidney (excretory) and the lungs (respiratory). The kidney will excrete a number of acid/base molecule based on the blood pH. When the body excess in H+, it will excrete acid to make the blood more base.

The respiratory will control the level of carbon dioxide. Carbon dioxide will be changed into bicarbonate and H + which makes the blood acidic. When the blood is acid, the carbon dioxide is removed more vigorously.