Physiological responses to stress

• The General Adaption Syndrome(GAS)


  Selye (1936)- Experimented with rats subjecting them to stress

  He found that it didnt matter what stressor it was, responses were same

  Concluded that stress is a general response of the body to any stressor

  Called his response GAS because it is general adoptive and a syndrome
• Stage 1- Reaction

  Trigger of adrenaline when threat is recognised

  Readiness for fight or flight
• Stage 2: resistance

  Stressor ends= normal levels

  Stressor continues= longer term stress response using up body resources

  Body appears to be coping but things are deteriating
• Stage 3: Exhaustion

  Resources needed to resist stressor are depleted

  Individual re-experiences intitial symptoms

  Immune system compramised, stress related illness are likely
• Acute stress: the SAM system


  Controls body's immediate response to an acute (immediately stressor)

  Fight or flight response

  Sympathetic branch of nervous system controls bodys automatic responses

  When stressor perceived this part of nervous system is triggered.

  The hypothalamus releases adrenaline into blood stream
• Acute stress: the SAM system 2

  Hormones circulate in blood and stimulate target organs

  Stressor I threat stops= parasympathetic nervous system returns our body to relaxed state

  Acute because system returns to normal quickly and doesn't damage the body.
• Chronic stress: the HPA system


  At the same time the SAM system is triggered so is the HPA system

  Hypothalamus activates the HPA system, triggering the release of hormone called CRF into blood stream

  Pituitary glands detect CRF which releases ACTH into bloodstream

  Outer portion of adrenal glands release cortisal
• Chronic stress: the HPA system 2

  CRF- ACTH- Cortisol

  Cortisol is central to body's physiological response to stress

  Cortisol is damaging to body as it suppresses the immune system

  HPA effect does self-regulate by monitoring cortisol levels in bloodstream and retracts CRF and ACTH which in turn lowers cortisol
• Evaluation

  Physiological stress response is different for males and females

  Taylor (2006) argued the fight or flight response only applies to males

  Females= nurturing, running away would eave offspring defenceless

  .Stressor met with protection and nurturing of offspring and befriending other female friends for social support
• Evaluation 2

  Suggests explanation of stress are biased

  Physiological response does not help us cope with modern stress

  Adaption from fight or flight for confronting an animal

  Modern world stressors like traffic jams doesnt apply

  Physiological stress is maladaptive in the modern world