Which is FALSE regarding the hypothalamic-pituitaryadrenal (HPA) axis and injury-associated stress?a. The HPA is initiated by the hypothalamus producing corticotropin-releasing hormone (CRH) in response to inflammatory cytokines
CRH acts on the anterior pituitary to stimulate the secretion of adrenocorticotropin hormone (ACTH) into the systemic circulation. ACTH acts on the zona fasciculata of the adrenal glands to synthesize and secrete glucocorticoids. Cortisol is the major glucocorticoid in humans and is essential for survival during significant physiologic stress. The resulting increase in cortisol levels following trauma has several important anti-inflammatory actions. Adrenal insufficiency represents a clinical syndrome highlighted largely by inadequate amounts of circulating cortisol and aldosterone. Classically, adrenal insufficiency is described in patients with atrophic adrenal glands caused by exogenous steroid administration who undergo a stressor such as surgery. These patients subsequently manifest signs and symptoms such as tachycardia, hypotension, weakness, nausea, vomiting, and fever.