Acid buffering systems in body
Acid / Alkaline Buffering Systems
The body’s pH Buffer systems correct both excess acidity and alkalinity,
but here the focus is on acid-buffering systems,
since over-acidity in the body is the
“problem of the day”
Overview of Body’s Acid- Buffering Systems
The body’s first step to counter acidosis - is to try and buffer excess acid with
alkaline mineral bicarbonates in the blood and lungs.
sufficient alkalizing minerals are unavailable -
the body begins to sweep the extra acids into the tissues,
especially muscles and joints. This is known as lactic acid ‘buildup’ and is
experienced as pain.
all else fails - the body will
precipitate acids out of solution in the form of solid crystals and salts,
realized as gallstones, kidney stones, uric acid crystals, plaque, and
Technical Details of Body’s Acid Buffering Systems
An acid buffer is made up of a buffering pair:
A weak acid
(capable of donating a H+ and thus lowering pH);
The acid’s conjugate base
(Capable of accepting H+,
and thus raising pH)
An acid-buffering system
is likened to a sponge which soaks up H+ ions - When an acid is added to a solution, the pH change can be
minimized by the adequate presence of buffers, and to have this effect,
acid buffers have to be a weak acid
For example, carbonic acid (H2CO3) is an
Since carbon dioxide and water are the principal end products from carbohydrate,
protein and fat breakdown, carbon dioxide (CO2) is the most abundant
acid-forming substance produced by the body.
CO2 + water (H2O) in the blood forms carbonic
acid (H2CO3) a weak acid which ionizes to give
H+ (hydrogen ion) and HCO3- (bicarbonate ion).
The H+ in strong acids are completely
dissociated, but the H+ in weak acids are only partially dissociated and are
efficient at preventing pH changes.
3 main acid / alkaline buffer systems
In functional equilibrium with each other, there
are three main buffer systems contributing to the regulation of the acid-base
Buffer Systems -
blood, lymph, and intra/extracellular fluids;
(Gaseous exchange in the lungs)
breathing out CO2 deals with much of our acid excess.
Renal Mechanisms (Excretory
functions of the kidneys)
the kidneys serve primarily to excrete
protons created during the breakdown of different acids. This excretory system
is needed because the typical diet tends to present more H+ ions (protons) than
alkalizing substances that might neutralize them.