Date of Award
Sarah N. Thomas
Zola J. Drain
The General Adaptation Syndrome or the G.A.S. is the term applied to collective responses to physiological stress. It is initiated by any disturbance in the normal balance of the body functions. These responses affect humans, monkeys, and other animals. The three main physiological changes which occur as a result of stress are enlarged adrenals, shrunken lymphatic organs, and bleeding gastrointestinal ulcers. There are also concomitant changes in the hematocrit and the formed elements of blood. In particular, there is usually a decrease in lymphocytes and eosinophils accompanied by the increase in neutrophils and platelets.
Stress is defined as pressure, or the sum of the biological reaction, to any adverse stimulus. According to Miller, "These stimuli can be physical, mental, or emotional, internal or external, that tend to disturb the homeostasis of an organism" (5). The human body and mind are normally able to adapt to the stressors of new situations. This ability has definite limits "beyond which continued stress may cause a breakdown, although this limit varies from person to person" (5). Stressors are any factors that disturb homeostasis, producing stress. It was reported by Seyle in 1936 that a variety of noxious stimuli elicit a generalized syndrome consisting of the 1 2 hypotrophy and hyperfunction of the adrenal cortex, the involution of the thymus and the lymph nodes, and ulcerations in the stomach and intestines; this syndrome is a nonspecific response of the body to intense demand and has been named the General Adaptation Syndrome (G.A.S.) or the Biological Stress Syndrome (6). It is the hypotrophy of the adrenal cortex, and thymus that causes the decrease in the number of lymphocytes and eosinophils (1).
There have been many attempts to understand the complex intricacies of stress. The present study was undertaken in order to generate indicators of stress reactio~s in the .genus *Gerbillus, and to determine blood changes in response to induced stress. The results should elucidate the pattern of physiological adaptations in these animals and help to explain principles and processes of blood biochemistry. The data showed also provide further insight and information regarding the biology of gerbils and their close relatives. *
Moore, Bridget L., "The General Adaptation Syndrome in Gerbillus" (1994). McCabe Thesis Collection. 10.