Mechanisms of acid-base balance regulation

MECHANISMS OF ACID-BASE BALANCE REGULATION

                 The ratio of base / acid proprtions of buffer system depends upon rate/ amount of acid production (H+) . The (H+) has to be eliminated by the body to maintain acid base balance normal.

The mechanisms of acid base balance regulation is

 i. Respiratory Regulation

  • By increasing or decreasing rate of respiration to eliminate Co2.
  •  Alveolar ventilation provides the oxygen needed for oxidative metabolism and eliminates the CO2 produced by metabolic processes.
  • In the normal subject control mechanisms insure the maintenance of adequate oxygen supplies and keep pCO2 value in the region of 40+/- 5 mmHg.
  • Even a slight elevation of paCO2 results in immediate stimulation of pulmonary ventilation.
  • pO2 constitutes an effective stimulus to ventilation only when its value drops to less than 70 mmHg.

Renal Regulation

  • All variations of body fluid hydrogen ion concentration stimulate the appropriate regulatory processes in the kidneys.
  • The main functions of the renal regulation are:
    • Excretion of acid.
    • The retention of extant bicarbonates.
    • The production of new bicarbonates to replace that consumed in the buffering of nonvolatile acids.
  • Increase of plasma bicarbonate leads to the production of new bicarbonates by the excretion of protons into urinary buffer systems.
  • The protons are eliminated trough the formation of ammonium and the conversion of HPO42- to H2PO4-.
  • High hydrogen ion concentration stimulates the secretion of hydrogen ions, leading to an increase of ammonium ion concentration.
  • High pCO2 stimulates the renal reapsorption of bicarbonate while low pCO2 has the opposite effect.
Last modified: Monday, 28 November 2011, 7:31 AM