Final answer:
When the pH of the blood becomes more acidic, it signals an increase in CO2 and H+ concentrations, prompting the respiratory center to increase the rate of breathing, which helps to exhale more CO2 and consequently raise the blood pH back to normal.
Step-by-step explanation:
When the pH of the blood becomes more acidic, it implies an increase in hydrogen ion concentration (H+), often due to a rise in carbon dioxide (CO2) levels. The body maintains pH homeostasis through a buffer system involving carbonic acid (H2CO3) and bicarbonate (HCO3-). In the lungs, CO2 reacts with water to form H2CO3, which can then dissociate into H+ and HCO3-. A key regulator of this process is the respiratory system, particularly the respiratory center in the brain.
When chemoreceptors in the medulla and major arteries detect a fall in blood pH, they provide feedback to the respiratory center. The respiratory center responds by sending nerve impulses that increase the rate and depth of breathing. This acceleration of breathing results in more CO2 being exhaled, which decreases the concentration of H2CO3, reduces the level of H+ ions, and consequently, increases blood pH back toward normal levels.
The body's ability to adjust the rate of breathing to manage blood pH is crucial in avoiding acidosis, which occurs when blood becomes too acidic, and alkalosis, which occurs when blood becomes too alkaline. Therefore, when blood pH becomes more acidic, the respiratory center increases the rate of breathing to correct the pH imbalance.