<unk>  has several possible causes. An excess of acid is called acidosis and an excess in<unk> s is called alkalosis. Acidosis is much more common than alkalosis. The<unk>  is compensated by negative feedback to restore normal values. Acid-base balance is maintained by normal respiratory and renal excretions of carbon dioxide and acids respectively.
Acid-base imbalance
Acidosis
Hypercapnia
Respiratory losses
Nitrogen narcosis
Hypoventilation
Metabolic alkalosis
Metabolic acidosis