Which system helps to maintain stable blood pH?

The correct answer is the buffer system, as it plays a crucial role in maintaining stable blood pH levels in the body. The buffer system consists of various mechanisms that can quickly neutralize excess acids or bases that enter the bloodstream, thus preventing significant fluctuations in pH. This is vital because even slight changes in blood pH can have profound effects on cellular functions and overall homeostasis.

The buffer system includes bicarbonate, phosphate, and proteins that act to absorb excess hydrogen ions (H+) or release them as necessary to stabilize pH. For instance, when blood becomes too acidic (lower pH), bicarbonate ions can react with hydrogen ions to form carbonic acid, which decreases acidity. Conversely, if the blood becomes too basic (higher pH), carbonic acid can dissociate to release hydrogen ions, thereby lowering the pH back to its normal range.

Other systems mentioned, such as the respiratory system, do contribute to pH regulation through the control of carbon dioxide (CO2) levels and therefore influence the concentration of carbonic acid in the blood. However, the respiratory system acts over a longer time frame compared to the immediate response of the buffer system.

The nervous system, while it regulates many bodily functions, does not have a