Physiological Stress Responses Short term stress response The HPAA The HPAA The fight/flight response The fight/flight response Long term stress response The general adaptation syndrome The general adaptation syndrome

General Adaptation Selye (1936) Rats exposed to a variety of severe but non- lethal stressors Rats exposed to a variety of severe but non- lethal stressors Exercise, injury, mutilation, poisoning Exercise, injury, mutilation, poisoning A long-term response to stress was observed that was independent of stressor type A long-term response to stress was observed that was independent of stressor type

General Adaptation Alarm Immediate response to stressor Immediate response to stressor Fight or flight Fight or flightResistance Body tries to adapt to stressor Body tries to adapt to stressor Hormonal changes to cope with stress Hormonal changes to cope with stress Conservation of resources Conservation of resources Effects on activity level, feeding etc. Effects on activity level, feeding etc. Not necessarily harmful Not necessarily harmful

General Adaptation Exhaustion Total depletion of coping resources Total depletion of coping resources Metabolic changes Metabolic changes Decline in immune functioning Decline in immune functioning Increased susceptibility to infection Increased susceptibility to infection

General Adaptation Adrenal Glands become enlarged Stomach develops ulcers Thymus shrinks

General Adaptation Ethical objections to use of animals Deliberate infliction of pain & stress Deliberate infliction of pain & stress Could alternative methods have been used? Could alternative methods have been used? Problems generalising Rat and human physiology have similarities and differences Rat and human physiology have similarities and differences Human stress is mediated by psychological factors Human stress is mediated by psychological factors