Conclusion
The most important chemical reaction in the human body is
cellular respiration, since the end-products of the oxidation
of food (adenosine triphosphate, heat energy, carbon dioxide
and water) are vital in maintaining optimal metabolism.
Increased respiration leads to the acidification of body fluid,
hence pH must be tightly regulated.
The time-dependent pH homeostatic regulators
{Figure 4) have been discussed in this two-part article.
Short-term regulators and the concept of buffering
capacity were discussed in part one, while part two has
focused on the functions of the intermediate and longterm
homeostatic regulators of body fluid pH when the
buffering capacity has been exceeded. Arterial carbon
dioxide and hydrogen ion chemoreceptors inform the
respiratory control centres in the brain of any acid-base
disturbances.This disturbance is usually a potential acidosis
since metaboli.sm is geared to acidification of the blood.
The body responds to an acidosis by increasing the rate
and depth of respiration to remove carbon dioxide (an
indirect source of acid) from the body. If the respiratory
system fails to re-establish pH homeostasis of body fluids,
then the renal pH regulators excrete hydrogen ions,
thereby acting as a long-term homeostatic compensatory
mechanism. If they fail, an acidosis occurs, which results
in a disordered metabolism.