ABSTRACT
This chapter discusses only the reflexes involved in cardiovascular regulation. It presents the evidence for changes in reflex activity occurring with postnatal age. While the basic mechanisms of cardiovascular regulation are quite similar among species, the rates of maturation of the reflexes making up regulation of cardiovascular function vary according to species. The number of reports concerning the age of onset of cardiovascular reflex activity in the fetus and neonate indicate marked variability. Since the activity in different substations of the cardiovascular regulatory system can alter the basic regulation of the circulatory system by reflexes, a brief summary of the studies on maturation of vasoactive sites is warranted. Decerebration studies have shown that the maintenance of a normal arterial pressure and the baroreceptor reflex require the integrity of the lower brainstem. The arterial baroreceptor reflex was the earliest recognized, and the baroreceptors are usually considered the major feedback elements of the cardiovascular controlling system.
