Chapter 5 Organization of the stress response at the anatomical level

Abstract

Publisher Summary This chapter discusses the organization of the stress response at the anatomical level. The systemic stressors like internal and external environmental changes act either directly on pituitary adrenocorticotropic hormone (ACTH) cells, or have their action mediated by hypothalamic factors. Neural stressors, independent of their origin and chemical nature, influence ACTH release only through hypothalamic factors. Among several hypothalamic substances, the corticotropin releasing factor (CRF) represents the most predominant component in the release of ACTH from anterior pituitary cells. The CRF is taken up by specific membrane receptors of ACTH cells from the pituitary sinus blood and, following internalization, it stimulates the release of ACTH from these cells. CRF may be involved in physiological regulation of the autonomic nervous system in addition to the regulation of pituitary ACTH. Paraventricular CRF may be involved in both mechanisms: one group of CRF cells projects to the median eminence influencing ACTH release and the other group of cells projects to the brain-stem and the spinal cord, influencing the activity of autonomic nervous system neurons.