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GENERAL ADAPTATION SYNDROME (GAS) - Coggle Diagram
GENERAL ADAPTATION SYNDROME (GAS)
Selye (1936)
exposed rats to unpleasant stressors: extreme heat, extreme cold, extreme sound and light
they displayed a universal response to all stressors
researched the physiological response to stress in rats
short term, this is an effective response
in the long term (if stress is chronic), stress related illness can occur
stress reaction in his rats was identical. enlarged glands, shrinkage of the thymus gland, ulcers in the stomach and small intestine
GAS is a non-specific physiological response to any demand - STAGE 1 - ALARM REACTION
physiological changes associated with the emotional reactions to stressors are involved and the body experiences a ‘shock’ phase
hypothalamus signals the sympathetic nervous system which stimulates the adrenal medulla
a threat (stressor) has been perceived
this secretes secrete adrenaline and noradrenaline, which help increase heart rate, blood flow
prepares the body for 'fight or flight'
STAGE 2 - RESISTANCE
an increase in activity from another part of the adrenal gland, the adrenal cortex
The adrenal cortex is controlled by the amount of ACTH (adrenocorticotrophic hormone) in the blood, which in turn is controlled by the corticotrophin releasing factor CRF
Sympathetic nervous system activity declines thus adrenaline and noradrenaline secretion also declines
Levels of glucocorticoid hormones (mainly cortisol) are increased and these provide the energy, to 'resist' the stress
the body recovers from the initial ‘alarm’ and starts to cope with the situation
body appears to be coping, physiological resources are being consumed at an alarming rate.
STAGE 3 - EXHAUSTION
that blood sugar levels drop and stress-related illnesses are now likely
physical health is affected e.g. high blood pressure, heart disease, ulcers etc. can develop
continues bodily resources become depleted so that the adrenal glands cannot function efficiently due to previous over activity
Mental illness such as depression is common
strength
Selye (1936) - subjected rats to various stressors. found that the same typical collections of responses occurred regardless of the stressor.
the damage appeared after 6 to 48 hours
there is empirical support for its assumptions.
Selye was then able to track the rats’ response to a continuing stressor through the resistance and exhaustion stages.
validate the three stages of GAS
weakness
cause the same stress response in humans whose stress responses have a greater emotional and cognitive input.
rats are also more passive in their response to stress whereas humans generally respond more actively, for example humans try to find ways to lessen stressors
. Rats are physiologically different to humans, the types of stressors that rats are exposed to in experiments may not generalise to humans
cannot be generalised to humans
research aiming to support the GAS is that much of it is conducted on animals
weakness
ethical issues....