Final answer:
The respiratory system can respond to changes in pH within minutes by adjusting the respiratory rate to either expel more CO2 in the case of acidosis or retain CO2 in the case of alkalosis.
Step-by-step explanation:
The time it takes for the respiratory system to respond to changes in pH is quite rapid. In the case of metabolic acidosis, the respiratory rate can increase to expel more carbon dioxide (CO2), thereby raising the blood pH, which can happen within minutes. In terms of metabolic alkalosis, the respiratory system's response is to decrease the respiratory rate to retain CO2 and increase blood acidity, though this mechanism is less efficient than its counterpart for acidosis and has a limited range within which it can operate.
Buffer systems in the body, which include the chemical buffers in the blood, the respiratory tract, and the renal system, work at different rates. The chemical buffers react within seconds, the respiratory system adjusts blood pH within minutes by altering CO2 exhalation levels, and the renal system takes hours to days to mediate pH changes through excretion of hydrogen ions and conservation of bicarbonate.