What is HPA axis How is it responsible for stress management?
Where is the HPA axis?HPA axis activation, proceeding from the hypothalamus to the pituitary gland to the adrenal glands. Image courtesy of Brian M Sweis. Show
The hypothalamic-pituitary-adrenal axis, or HPA axis as it is commonly called, describes the interaction between the hypothalamus, pituitary gland, and adrenal glands. The hypothalamus and pituitary gland are located just above the brainstem, while the adrenal glands are found on top of the kidneys. What is the HPA axis and what does it do?The main function generally attributed to the HPA axis involves the body's reaction to stress. When something stressful happens to us, our initial response is mediated by the sympathetic nervous system. This response occurs almost immediately, and results in the secretion of epinephrine and norepinephrine, both of which work to enact changes that you would generally expect if you felt stressed and/or frightened, like increased heart rate and perspiration. About 10 seconds later, the HPA axis is stimulated. The hypothalamus responds to signals like elevated norepinephrine levels by secreting corticotropin-releasing hormone into the bloodstream. Corticotropin-releasing hormone (also known as corticotropin releasing factor or CRH or CRF for short) itself increases the activity of the sympathetic nervous system, perpetuating effects like elevated heart rate. CRH, however, also tells the pituitary gland to secrete a substance called adrenocorticotropic hormone (ACTH) (for more on how the hypothalamus and pituitary gland communicate, see this article). The pituitary gland releases ACTH into the bloodstream, and the hormone travels down to the adrenal cortex, which is a term for the outer layer of the adrenal glands. ACTH binds to receptors on the surface of the adrenal cortices, leading to a series of intracellular events that result in the adrenal glands secreting glucocorticoids like the hormone cortisol. What is the HPA axis and how does it work?A major component of the homeostatic response is the hypothalamic-pituitary-adrenal (HPA) axis, an intricate, yet robust, neuroendocrine mechanism that mediates the effects of stressors by regulating numerous physiological processes, such as metabolism, immune responses, and the autonomic nervous system (ANS).
What is the HPA axis in stress?The hypothalamic-pituitary-adrenal axis, or HPA axis, is a term used to represent the interaction between the hypothalamus, pituitary gland, and adrenal glands; it plays an important role the body's response to stress. The pathway of the axis results in the production of cortisol.
Why is it called HPA axis?The hypothalamic-pituitary-adrenal axis, or HPA axis as it is commonly called, describes the interaction between the hypothalamus, pituitary gland, and adrenal glands. The hypothalamus and pituitary gland are located just above the brainstem, while the adrenal glands are found on top of the kidneys.
What is the purpose of the HPA?The HPA was developed to regulate health professions in a way that allows for non-exclusive, overlapping scopes of practice.
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