This document discusses psychosomatic disorders, which involve physical symptoms caused by mental or emotional factors rather than physical pathology. It defines psychosomatic disorders and outlines the psychological and physiological mechanisms by which stress can influence bodily functions. Specifically, it describes how stress activates the hypothalamic-pituitary-adrenal axis and sympathetic nervous system, releasing hormones like cortisol and catecholamines that can induce immune, inflammatory, and pain responses when the body is chronically stressed. The document also introduces the concept of somatization, where psychological distress becomes manifested as physical symptoms.