Acid -base balance
The body's balance between acidity and alkalinity is referred to as acid-base balance.Blood acidity increases when the
o Level of acidic compounds in the body rises (through increased intake or production,
or decreased elimination)
o Level of basic (alkaline) compounds in the body falls (through decreased intake or
production, or increased elimination)
Blood alkalinity increases when the level of acid in the body decreases or when the level of
base increases.Types of acidosis and alkalosis
Acidosis and alkalosis are classified depending on their primary cause as
o Metabolic
o Respiratory
Metabolic acidosis and metabolic alkalosis are caused by an imbalance in the production of
acids or bases and their excretion by the kidneys.In clinical settings, we evaluate person's acid-base balance by measuring the pH and levels of
carbon dioxide (an acid) and bicarbonate (a base) in the blood.Types of Acid-Base Disorders
There are two abnormalities of acid-base balance:
o Acidosis: The blood has too much acid (or too little base), resulting in a decrease in
blood pH.
o Alkalosis: The blood has too much base (or too little acid), resulting in an increase in
blood pH.
Acidosis and alkalosis are not diseases but rather are the result of a wide variety of disorders.The respiratory center regulates the amount of carbon dioxide that is
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exhaled by controlling the rate and depth of breathing (ventilation).Respiratory acidosis and respiratory alkalosis are caused by changes in carbon dioxide
exhalation due to lung or breathing disorders.Controlling pH involves the use of chemical buffer systems, which
guard against sudden shifts in acidity and alkalinity.As carbon dioxide accumulates in the blood, the pH of the blood decreases
(acidity increases).Compensation for acid-base disorders
Each acid-base disturbance provokes automatic compensatory mechanisms that push the blood
pH back toward normal.Hemoglobin and oxyhemoglobin, protein and
phosphate buffer pairs.The pH buffer systems are combinations
of the body's own naturally occurring weak acids and weak bases.The kidneys are able to affect
blood pH by excreting excess acids or bases.2.3.