ACID-BASE REGULATION AND DISORDERS

Hydrogen ion (H⁺) is especially reactive; it can attach to negatively charged proteins and, in high concentrations, alter their overall charge, configuration, and function Acid-base equilibrium is closely tied to fluid and electrolyte balance, and disturbances in one of these systems often affect another

Acid-Base Physiology

Most acid comes from carbohydrate and fat metabolism, which generates of CO₂ daily. CO₂ is not an acid itself but combines with water (H₂O) in the blood to create carbonic acid (H₂CO₃), which in the presence of the enzyme carbonic anhydrase dissociates into H+ and HCO₃^-. The H⁺ binds with hemoglobin in RBCs and is released with oxygenation in the alveoli, at which time the reaction is reversed, creating H₂O and CO₂, which is exhaled in each breath

CELLULAR MECHANISMS OF Cl− ABSORPTION AND SECRETION

Cl^- absorption occurs throughout the small and large intestine and is often closely linked to Na⁺ absorption. Cl⁻ and Na⁺ absorption may be coupled through either an electrical potential difference or by pH_i. However, sometimes no coupling takes place, and the route of Cl⁻ movement may be either paracellular or transcellular.