ABSTRACT
The major function of the respiratory system is to maintain normal arterial blood partial pressures of the two vital respiratory gases, O2 and CO2, and a normal pH. This important regulatory function is automatically controlled, and is referred to as the homeostatic (chemostatic or metabolic) function. Homeostatic regulation is achieved by adjustment of ventilation to the metabolic (O2 consumption=CO2 production) and acid-base needs of the organism (1). The respiratory system is also utilized for behavioral (nonhomeostatic) functions such as phonation and swallowing. The act of breathing, therefore, is complex and needs to be governed precisely by a set of hierarchically arranged control systems. The focus of this chapter is chemical control of breathing and regulation of PCO2.
