Biochemistry of Acid Base Balance

Hydrogen ions are present in all body compartments. Maintenance of appropriate concentration of hydrogen ions is critical to normal cellular function. The acid base balance or pH of body fluids is maintained by closely regulated mechanism and this mechanism involves body buffers, respiratory system and renal system.

Acids and Bases

Definition: Acids are the substances that are capable of donating protons and bases are those that accept the protons.

Weak and strong acids and bases:

A strong acid is one that completely discharges the hydrogen ions into the solution. E.g. HCl

A weak acid is the one which partially discharges the hydrogen ions into the solution.eg. H2CO3

A strong base is the one that reacts powerfully with hydrogen ions and therefore removes the hydrogen ions from the solution. E.g. hydroxyl ion

A weak base is the one that binds weakly with the hydrogen ions. E.g. HCO3

pH

pH is defined as the negative logarithms of hydrogen ion concentration.

This means that if the pH is low then hydrogen ion concentration is high acid it is called as acidosis. Whereas vice versa is called as alkalosis.

Buffers

Buffers are the solutions which can resist the changes in the pH when acid or base is added. Buffers can be of two types:

1. Mixture of weak acids with their salt with a strong base.
2. Mixture of weak base with their salt with strong acid.

Common examples of buffers present in the body are phosphate buffer, bicarbonate buffer etc.