Acido-basic metabolism

The acido-basic metabolism is the part of the Métabolisme controlling the Acidité Sang since blood pH must remain between very narrow physiological limits, are 7.38 and 7.42. With the top of 7.42 one speaks about Alcalose, in lower part of 7.38, of Acidose, both being able to be of metabolic or respiratory origin.

Sources of acids and bases

The acid or basic sources are numerous, particularly for the acids which are drawn from the Aliment S and the metabolism interns (cellular Respiration: the Carbon dioxide is a Acide which combines with the Eau). The bases come from these same sources but of more restricted number.

Control mechanisms of balance acid-bases

To maintain the pH more nearly 7.40, intervene of powerful systems plugs. The amphoteric Proteins, the phosphates, the Hemoglobin of the red Globules and the bicarbonates take part in the fine regulation of the pH. Thus the plasmatic concentration of the Bicarbonate S is six hundred and thousand that of the

H^+

, which makes it possible to plug the ions

H^+

nonrespiratory source through the reaction:

H^+ + HCO_3^- \ rightarrow H_2CO_3 \ rightarrow CO_2 + H_2O

the d' $H^+$ addition pushes the reaction towards the line, modifying the pH little (but $HCO_3^-$ decreases and $CO_2$ increases). Contrary, an increase in $CO_2$ moves balance on the left.

Moreover ventilation the rejection of the $CO_2$ allows to maintain constant its partial pressure in blood and the kidneys ensure a control of the réabsorbtion of the Bicarbonate S and the secretion (or réabsorbtion) of the Ion S $H^+$ .

See too

Internal bonds

Random links: