Acid Base Balance
There are many anions and cations within body fluids.
One of the most important of these is the hydrogen ion (H+) even though it is present in comparatively low concentrations.
The concentration of Na+ is one million times greater than H+ . [2] Therefore, to ease interpretation of the H+ concentration [H+], it is expressed as pH:
pH = log[H+] |
As the [H+] increases, pH decreases. Normal pH within the body is 7.35-7.45 (equivalent to a H+ ion concentration of 35-45 nmol/litre) at which enzyme reactions are optimised. [3]
A buffer is a weak (incompletely ionised) acid or base which minimises changes in pH by taking up or releasing H+. [3]
Within body fluids, there are multiple buffer systems, for example bicarbonate, phosphate and plasma proteins. Additionally, within blood, haemoglobin acts as a buffer. [3]