ABSTRACT
In health, normotension is maintained by matching blood volume to blood vessel capacity. This is achieved through autonomic reflexes and endocrine responses.
1 Hypotension is sensed by baroreceptors in major arteries, which activate the hypothalamic-pituitary-adrenal (HPA) axis (the stress response – fight or flight). More adrenocorticotrophic hormone (ACTH) is released by the pituitary gland, which stimulates adrenal production of adrenaline and noradrenaline, causing vasoconstriction. HPA axis activation also increases glucocorticoid secretion (O’Connor et al., 2000).
