Physiology, Stress Reaction

Excerpt

Any physical or psychological stimuli that disrupt homeostasis result in a stress response. The stimuli are called stressors and physiological and behavioral changes in response to exposure to stressors constitute the stress response. A stress response is mediated by a complex interplay of nervous, endocrine, and immune mechanisms that involves activation of the sympathetic-adreno-medullar (SAM) axis, the hypothalamus-pituitary-adrenal (HPA) axis, and immune system. The stress response is adaptive, to begin with, that prepares the body to handle the challenges presented by an internal or external environmental challenge (stressor) e.g., the body's physiologic responses to trauma and invasive surgery serve to attenuate further tissue damage. But if the exposure to a stressor is actually or perceived as intense, repetitive (repeated acute stress), or prolonged (chronic stress), the stress response becomes maladaptive and detrimental to physiology e.g., exposure to chronic stressors can cause maladaptive reactions including depression, anxiety, cognitive impairment, and heart disease.