The buffer systems
The lungs, kidneys, and the buffer system are the primary considerations in the homeostatic process. The lungs can control certain small amounts of carbon dioxide in the blood.
Carbon dioxide in the blood chemically produces carbonic acid. Thus, in cases where the lungs do not function properly, CO2 builds up, causing increased carbonic acid. This increase in acid can affect the blood pH, leading to acidosis. The main function of kidneys is retaining or excreting of the bicarbonate ion (HCO3). This is the ion which neutralizes the excess acid in the blood. If both organs are working properly, the natural build?up of acids can be neutralized effectively by the buffer system.
The buffer system in the body is able to work very quickly to maintain proper pH of the blood and body tissues. The prime buffer system is the system of carbonic acid and bicarbonate. Bicarbonate will neutralize the correct numbers of carbonic acid molecules to maintain the correct ratio of 20:1 acid molecules. This 20:1 ratio will preserve the blood pH at the normal range of 7.35 to 7.45. Bicarbonate ions and carbonic acid are constantly being produced and combined in order to keep the optimal pH.
The respiratory system also works to maintain the proper blood pH. When the bicarbonate/carbonic acid buffer system cannot work fast enough to compensate for pH disturbances, the respiratory system has a mechanism for buffering the blood. Hyperventilation and hypoventilation can be used by the body to control the amount of carbonic acid in the blood.
The respiratory center in the brain responds to changing levels of carbonic acid in the blood. When the acid level of blood increases, and is not controlled by the first buffer system, the respiratory system responds.
Hyperventilation causes the body to exhale and "get rid of" CO2 from the blood, through the lungs. This reduction of CO2 causes the blood pH to become less acid. Reduce the CO2 and the acid level of the blood is reduced. This is how the body responds to excess acid in the blood.