Pub. date: 2004 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412952576 | Print ISBN: 9780761923602 | Online ISBN: 9781412952576 | Publisher:SAGE Publications, Inc.About this encyclopedia
General Adaptation Syndrome
Shira Lipsky & Rebecca Kentor & Gabriella Rothman & William Gerin
Modern ideas regarding stress and its effects on the body date from the classic work of physiologist Walter Cannon (1929). Cannon studied the physiological processes involved in the maintenance of homeostasis and observed what he called the fight-or-flight response. The fight-or-flight response involves a chain of biochemical reactions that begin with the stimulation of the cerebral cortex once the threat has been perceived. Among other responses, the cerebral cortex triggers the hypothalamus, which activates the sympathetic nervous system, which, in turn, stimulates the adrenal cortex to secrete cortisol and the adrenal medulla to secrete the hormones epinephrine and norepinephrine (catecholamines). The circulation of these hormones triggers the physiological processes associated with the fight-or-flight response, including increases in heart rate, respiration, blood pressure, blood volume, blood sugar, and blood flow to the muscles and brain, and inhibition of major bodily systems such as digestion and reproduction. Together, these physiological changes act ...