Stress- The Body's Response to Stress

• Fight or flight response- an immediate stressor that is not long lasting e.g. a shock or a deadline. Cannon 1914- Dates back to prehistoric times

HYPOTHALAMUS: Releases CRF to the SNS

SYMPATHETIC NERVOUS SYSTEM: Sends noradrenaline to the adrenal medulla

ADRENAL MEDULLA: Converts noradrenaline into adrenaline ready for fight or flight

• The fight or flight response increases heart rate, inhibits saliva production
• The parasympathetic nervous system kicks in when the stressor is no longer there- this inhibits the fight or flight response 
• The problem with the SAM system is that if the stress does not go away, we get exhausted and this can lead to health problems. 

• When the SAM system cannot cope and the stressor becomes chronic, the HPA system kicks in.

HYPOTHALAMUS: Releases CRF to the pituitary gland

PITUITARY GLAND: Sends ACTH through the blood to the adrenal cortex

ADRENAL CORTEX: Sends cortisol around the body

The hypothalamus checks if the stressor is still present and if it is the cycle continues

• Cortisol enables the breakdown of glucose to provide energy so the person can keep fighting the stressor.
• Can cause problems with thinking, high blood pressure and lowered immune functioning. Can lower serotonin. 

Three stages of the General Adaptation Syndrome:

• Alarm stage- the presence of a stressful event is registered. The body is prepared for energy expenditure and thus poised for the fight or flight response.
• Resistance stage- The stress response is activated and so the body is seemingly coping with the stressor and so from the outside things appear to be under control.
• Exhaustion stage- If the stressor is chronic the body becomes exhausted. Hormone reserves become depleted and the body experiences raised blood pressure, ulcers, depression and anxiety, may develop. 

• Many psychologists believe that the way our ancestors dealt with stress has led to different stress responses in men and women.
• In 2005, 70% of under 75's who died of CHD were men and 30% were women
• They argue that females have a greater investment in their offspring and therefore evolution has lead females stress response to no jeopardize the safety of offspring. 
• Shelley Taylor et al (2000) believe that this should favour the development of biological mechanisms which inhibit the fight or flight response in females when they are faced with a threat. Females would attend to their young and befriend other females as a defense mechanism.