pH buffering system

The pH buffering system refers to a collection of **physiological, biochemical, and chemical mechanisms** that stabilize hydrogen ion concentration in biological fluids, thereby maintaining pH homeostasis[2][3][4][7][9]. The most notable systems are composed of weak acids and their conjugate bases—such as the carbonic acid (H₂CO₃)/bicarbonate (HCO₃⁻) buffer system in blood, the phosphate buffer in cells and urine, and protein buffers (notably hemoglobin in red blood cells)[3][5][7][8]. These systems act to absorb excess acid or base through reversible chemical reactions, preventing significant deviations in pH, which is essential for proper cellular function, enzyme activity, and overall organismal survival[1][2][3][7][9]. The buffering capacity of these systems is finite, and when exceeded, pathological states including acidosis and alkalosis may develop[6][7][9]. Pharmacological agents such as sodium bicarbonate or antacids clinically exploit these principles to correct pH imbalances. Key note: - This entry does **not represent a molecular target** (such as a receptor, enzyme, or transporter), and thus is **incorrect as a drug target entity**. Instead, it encompasses a principle/process and comprises multiple buffer systems and chemical equilibria fundamental to physiology[2][3][4][5][9].

Other names

hydrogen ion buffering systemacid-base buffering systemphysiological buffering systembody buffer system

Direct buffering of excess H⁺ or OH⁻ ions (by drugs like bicarbonate) Modulation of renal acid/base excretion Altering CO₂/HCO₃⁻ equilibrium (e.g., via carbonic anhydrase inhibitors)