Physiological response

• SAM Acute Stress response

  • hypothalamus detects stressor and an increases sympathetic nervous system activity
  • sympathetic nervous system signals adrenal medulla and adrenaline is released
  • fight or flight response occurs
• HPA Chronic Stress response

  • hypothalamus releases corticotropin releasing hormone
  • pituitary gland detects CRH and produces adrenocorticotrophic hormone
  • adrenal cortex detects ACTH and releases cortisol
• General Adaptation Syndrome

  • made by Selye
  • claims that stress response has three stages and can help us adapt to new situations
• What is the first stage in Seyle's GAS theory?

  Alarm:

  • initial physiological response
  • body’s resources briefly decreased to prepare for fight or flight
• What is the second stage in Seyle's GAS theory?

  Resistance:

  • the body adapts by ceasing fight or flight response, but still continues to use more resources than normal to resolve the stressor as quick as possible
  • individual appears to be coping but resources gradually deplete
• What is the third stage in Seyle's GAS theory?

  Exhaustion:

  • if stress is long-term, body can no longer maintain normal functioning due to resources being used up
  • fight or flight symptoms reappear and "diseases of adaptation" start to occur (stress-related illness)
• Physiological response evaluation:

  + scientific approach :

  • theory heavily rooted in science and uses scientific methodology to investigate stress
  • increases validity and reliability
  • features of science: allows establishment of cause and effect

  - Taylor et al. :

  • suggested women have different sympathetic nervous system response of "tend and befriend" instead of "fight or flight"
  • suggests beta bias

  - research bias :

  • most studies on stress were done on men
  • suggests results cannot be generalised to women
• Seyle's General Adaptation Syndrome Evaluation:

  + Seyle study:

  • exposed rats to extreme stressors
  • within 6 to 48 hours, all rats responded in the same way
  • suggests stress response is general

  - counterpoint to Seyle's study:

  • uses rats so cannot generalise to humans as physical structure is different

  - Mason study

  • replicated Seyle's study with monkeys and found that different stressors had different responses
  • challenges the GAS model

  - individual differences

  • different stressors will create different responses
  • different people will respond to different stressors differently
  • suggests Seyle's theory was too general
• Role of cortisol

  • provides the body with glucose from liver storage, which can help an individual fight or flee a stressor
  • anti-inflammatory role that weakens of the immune system and increases the likelihood of infections
  • constricts blood vessels and increases blood pressure to make delivery of oxygenated blood more efficient for fight-or-flight situations. over time, leads to vessel damage and plaque build-up, which can lead to cardiovascular disorders