Biological Chemistry - Berezov T. T., Korovkin B. F. 1998

Blood
Blood buffer systems and acid-base balance

The constancy of the internal environment pH is maintained through the combined action of Buffer systems and A number of physiological mechanisms. The latter include the respiratory activity of the Lungs and the Excretory Function of the Kidneys.

Acid-base balance is the relative constancy of the internal environment reaction, quantitatively characterized either by the concentration of hydrogen ions (protons) expressed in moles per liter, or by the hydrogen exponent—the negative decimal logarithm of this concentration—pH (power of hydrogen).

The "first line of defense" in living organisms that prevents Changes in the pH of their internal environment is provided by the Blood Buffer Systems.

A buffer system* is a conjugate acid-base pair consisting of a proton (hydrogen ion) acceptor and donor.

The behavior of Buffer solutions is described by the Henderson–Hasselbalch equation, which relates the pH value to the acidity constant

(K):

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The Henderson–Hasselbalch equation makes it possible to calculate the pKa value of any acid at a given pH (if the molar concentration ratio of the proton donor to acceptor is known), determine the pH value of a conjugate acid-base pair at a given molar ratio of the donor and proton acceptor (if the pKa value is known), and calculate the ratio between the molar concentrations of the proton donor and acceptor at any pH value (if the pKa value of the weak acid is known).



Last update: 06/08/2026

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