Selye argued that stressors produce the same reaction in all animals (including humans). He called this the General Adaptation Syndrome (GAS), and identified three main stages: 1) alarm - the body is mobilized for swift ‘fight or flight’ responses; 2)resistance - if a stressor persists, the release of hormones from the pituitary gland and the adrenal cortex increases and the alarm symptoms of the first stage subside, giving the appearance of a return to normal physiological functioning; 3)exhaustion - if the stressor persists for longer than the body’s defences can cope with, then the adrenal glands cease to function normally and there is a drastic fall in blood sugar levels.