AEMCA Practice Exam

How does the bicarbonate buffering system work in the body?

1. By producing hemoglobin

2. By converting lactic acid into glucose

3. By dissociating into bicarbonate and hydrogen ions

4. By storing excess energy

The correct answer is: By dissociating into bicarbonate and hydrogen ions

The bicarbonate buffering system plays a crucial role in maintaining the pH balance in the body, particularly in the blood. This system operates through a dynamic equilibrium that involves the dissociation of carbonic acid, which is formed when carbon dioxide (CO2) dissolves in water. When the body needs to buffer excess acidity, carbonic acid dissociates into bicarbonate ions (HCO3-) and hydrogen ions (H+). The hydrogen ions then combine with stronger acids in the body, which helps to reduce the overall acidity, thus stabilizing the pH level. Conversely, when the body becomes too alkaline, bicarbonate can combine with excess hydrogen ions to form carbonic acid, which can then dissociate into water and carbon dioxide that is expelled from the body via respiration. This ability to shift between forms allows the bicarbonate buffering system to effectively manage pH changes in biological fluids, making it essential for enzyme function and overall metabolic processes. Through this mechanism, the bicarbonate buffering system helps maintain homeostasis in the body. Other options do not directly relate to the functioning of the bicarbonate buffering system; for example, hemoglobin is involved in oxygen transport rather than buffering, while the conversion of lactic acid to glucose is part of