acid-base metabolism, the metabolic processes that maintain the balance of acids and bases essential in regulating the composition of body fluids. Acids release hydrogen ions, and bases accept them; the concentration of hydrogen ions present in a solution governs whether it is acid, alkali, or neutral. Hydrogen ions in water are measured on a pH scale of 0.0 to 14.0, with a reading of 7.0 indicating neutral at 25° C. Above 7.0, the solution is alkaline; below, it is acid. Blood is slightly alkaline, ranging from 7.35 to 7.45. Metabolic buffer systems within the body maintain this ratio, and when the ratio is upset, acidosis or alkalosis results. Acidosis may be caused by diarrhea, vomiting, uremia, diabetes mellitus, and the action of certain drugs. Alkalosis may be caused by overingestion of alkaline drugs, loss of chloride in gastric vomitus, and the action of certain diuretic drugs. See also acid-base balance, acidosis, alkalosis, pH.
