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4. The Cardiovascular System
~ the modern biomedical context
To the Heart of the Matter
Classical physiology has developed descriptions of the primary extrinsic CV control mechanisms
mediated by the ANS and its regulation by the catecholamines (see appendicies; I: table 1., II: fig.
1., III: table 2. & IV: fig. 2.). Within these descriptions, the CV system dynamics are presented in
relation to discrete disassociated processes that involve system specific regulatory mechanisms. The
application of this understanding has dictated the mechanistic approach to CV illness aetiology
throughout the nineteenth and most of the twentieth centuries (Sterling & Eyer 1981).
Extending this model, PNE has integrated emotional states into the description of the CV regulatory
processes. This development has been concurrent with the progress in the aetiological
understanding of CV illness. It has been shown that psychological factors can dysregulate the CV
system control mechanisms, mediated by the interaction of the ANS, the hypothalamic-pituitary-
adrenocortical axis (HPA) (see appendix V: table 3 & fig. 3.) (Appels 1997) and neurotransmitter
activity (Thase & Howland, 1995). This can result in disturbances of CV system function, resulting
in the development of CV illness.
The model of the CV system that has developed within PNE, is one where the CV system is
understood as been intimately related to the emotional state of the individual. Nixon & King (1997,
p. 49) write: “The role of the emotional arousal in the genesis of heart diseases and sudden coronary
death is commonly dismissed as anecdotal, but the development of appropriate technology is
bringing it into the realm of probability and scientific approbation”.
The following discussion presents the mechanisms, which form the basis for a biomedical
understanding of the CV system in relation to emotional responses. Presented are some of the more
intricate interrelationships, which are propose a mind-body approach to understanding the integrated
role of CV system regulation and activity.
4.1. The Role of the Hypothalamic-Pituitary-Adrenocortical Axis
The role of the HPA axis in CV regulation is primarily mediated by the glucocorticoids. These are
produced in response to adrenocorticotropic hormone (ACTH) production, which is stimulated by
the release of corticotropin releasing factor (CRF) from the hypothalamus (see appendix V: table 3
& fig. 3.).
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