Porth's Essentials of Pathophysiology, 4e

tress, adaptation, and their relationship to health are a frequent topic of discussion. The human body and mind respond to stress by activating a com- plex repertoire of physiologic and behavioral adap- tive responses which, if inadequate or excessive, may affect emotional behavior and have adverse effects on physiologic functioning. Stress may contribute directly to the production or exacerbation of a disease, or it may contribute to the development of behaviors such as smoking, overeating, and drug abuse that increase risk of disease. The content in this chapter has been organized into two sections: the first focuses on stress and adaptation and the second on disorders of the stress response. Stress and Adaptation A variety of definitions have been ascribed to the phe- nomenon of stress. The concept of stress has been studied extensively by physiologists, psychologists, soci- ologists, and members of the health care professions. The nature of these disciplines and the individual work of their members have led to rather disparate bodies of knowledge about stress. Despite these disparities, the concept of stress is commonly viewed within the con- text of three major components: homeostasis, the stress response, and adaptation to stress. Homeostasis The concepts of stress and adaptation have their origin in the complexity of the human body and interactions between the body’s cells and its many organ systems. These interactions require that a level of homeostasis or constancy be maintained during the many changes that occur in the internal and external environments. In effecting a state of constancy, homeostasis requires feed- back control systems that regulate cellular function and integrate functions of the different body systems. Constancy of the Internal Environment The environment in which body cells live is not the external environment that surrounds the organism, but S Stress and Adaptation 9 C h a p t e r

Stress and Adaptation Homeostasis

Constancy of the Internal Environment Control Systems The Stress Response Neuroendocrine Responses Immune Responses Adaptation to Stress

Control Mechanisms Adaptive Mechanisms Disorders of the Stress Response Effects of Acute Stress Effects of Chronic Stress

Posttraumatic Stress Disorder Treatment of Stress Disorders Progressive Muscle Relaxation Techniques Guided Imagery Music Therapy Massage Therapy Biofeedback

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