Stress, Endocrine Physiology and Pathophysiology
Stress is a state of threatened homeostasis caused by intrinsic or extrinsic adverse forces (stressors) and is counteracted by an intricate repertoir of physiologic and behavioral responses aiming to maintain/reestablish the optimal body equilibrium (eustasis) The adaptive stress response depends upon a highly interconnected neuroendocrine, cellular and molecular infrastructure, the stress system. Key components of the stress system are the hypothalamic pituitary adrenal (HPA) axis and the autonomic nervous system (ANS) which interact with other vital centers in the central nervous system (CNS) and tissues/organs in the periphery to mobilize a successful adaptive response against the imposed stressor(s) Dysregulation of the stress system (hyper or hypo activation) in association with potent and/or chronic stress can markedly disrupt the body homeostasis leading to a state of cacostasis or allostasis, with a spectrum of clinical manifestations. This chapter describes the organization and physiology of the stress system, focusing on its interactions with other CNS centers and endocrine axes, and reviews the existing evidence linking stress to pathophysiologic mechanisms implicated in the development of stress related diseases affecting the endocrine, metabolic, gastrointestinal and immune systems. For complete coverage of this and all related areas of Endocrinology, please visit our FREE web book, www.endotext.org