- 1. A mixture of an acid and its conjugate base (salt), such as H2CO3/HCO3−; H2PO4−/HPO42−, that, when present in a solution, reduces any changes in pH that would otherwise occur in the solution when acid or alkali is added to it; thus, the pH of the blood and body fluids is maintained relatively constant (pH 7.45) although acid metabolites are continually being formed in the tissues and CO2 is lost in the lungs. SEE ALSO: conjugate acid-base pair. 2. To add a b. to a solution and thus give it the property of resisting a change in pH when it receives a limited amount of acid or alkali.- dipolar b. SYN: zwitterionic b..
* * *buff·er 'bəf-ər n1) a substance or mixture of substances (as bicarbonates and some proteins in biological fluids) that in solution tends to stabilize the hydrogen-ion concentration by neutralizing within limits both acids and bases2) BUFFER SOLUTIONbuffer vt to treat (as a solution or its acidity) with a buffer also to prepare (aspirin) with an antacid
* * *n.a solution whose hydrogen ion concentration (pH) remains virtually unchanged by dilution or by the addition of acid or alkali. The chief buffer of the blood and extracellular body fluids is the bicarbonate (H2CO3/HCO3-) system. See also acid-base balance.
* * *buf·fer (bufґər) 1. a chemical system that prevents change in the concentration of another chemical substance, e.g., proton donor and acceptor systems that prevent marked changes in hydrogen ion concentration (pH). 2. a physical or physiological system that tends to maintain constancy, e.g., reflexes regulating blood pressure.
Medical dictionary. 2011.