[libribook.com] Traumatic Scar Tissue Management 1st Edition

Figure 7.2
Summay of the normal stress cascade with return to homeostasis.
In times of acute stress, SNS mediated release of hormones readies us to respond
to threat, real or perceived, by driving a host of physiological and psychological
changes. Heart rate, blood pressure and respiration rate changes enable quick
actions to be taken (e.g. fight or flight). Skeletal muscle acquires additional
energy from adipose and hepatic cells. Suppression of normal thought functions
enables our brain to switch into survival mode, further supporting the ability to
react quickly without the usual time taken for evaluation and planning. Such
changes are considered beneficial adaptations.
In the absence of stress or under normal circumstances, the parasympathetic
nervous system (PSNS) governs self-preservative functions, such as homeostasis
and wound healing (van der Kolk 1994). During stress response, SNS
predominance will suppress or alter functions that are normally governed by the
PSNS.
As previously noted, stress response is generally short-lived, lasting only long
enough to get us out of harm’s way. All inessential activity in-the-moment (e.g.
digestion, reproduction, feeding and growth) will be supressed, largely through
actions exerted by glucocorticoids (Vitlic et al. 2014). Typically there is an
eventual return to homeostasis as the PSNS returns to the driver’s seat. Although
stress response is normally short-lived, certain circumstances can set the stage
for prolonged or chronic (pathophysiological) stress response and in turn this can
adversely impact wound healing – more on this later in this chapter.