In human body, there are chemoreceptors which respond to the
levels of carbon dioxide in the blood,
These receptors are located in the brainstem (midbrain and
medulla oblongata region) and basically deals with the regulation
of pH within the body fluids.
Carbon dioxide in blood is being converted to an acidic form of
carbonic acid after interaction with water further getting
dissociated to release hydrogen ions. Any component able to
liberate hydrogen ions is termed as an acid. Thus, these
specialized chemoreceptors helps in detecting the increasing levels
of carbon dioxide in blood and mediate a response in the form of
rapid breathing to increase influx of oxygen.