fight or flight response

• the fight or flight response is a sequence of activity within the body that is triggered when the body prepares itself for defending or attacking (fight) or running away to safety (flight) - involves the nervous system and secretion of hormones
• how is the amygdala associated with the fight or flight response

  • amygdala associates sensory signals (vision, hearing) with fear
  • sends a distress signal to hypothalamus
  • communicates with the rest of the body via sympathetic nervous system
• what responds to acute (sudden) stressors?

  sympathetic adrenal medullary system (SAM)
• explain the SAM system


  • hypothalamus - directs the
  • sympathetic branch of ANS to send messages via NTs to
  • adrenal gland
  • adrenal medulla secretes adrenaline which
  • constricts blood vessels and increases heart rate
  • adrenal medulla secretes noradrenaline which
  • increases blood sugar levels
• what response to chronic stressors

  hypothalamus pituitary adrenal axis (HPA axis)
• explain the HPA axis

  • hypothalamus releases CRH into the bloodstream in response to stressor
  • CRH causes pituitary gland to release ACTH
  • ACTH transported to target site in adrenal glands via blood
  • adrenal cortex secretes cortisol - bursts of energy + lower pain sensitivity, lowers immune system
  • adrenal cortex secretes glucocorticoids which increase body's energy levels
• if cortisol levels are too high, the hypothalamus and pituitary glands inhibit the release of CRH and ACTH repectively
• limitation - tend and befriend response

  • females may display different response to stress
  • protect themselves and young through nurturing behaviours (tend) and forming alliances with other women (befriend)
  • responses evolved from being the primary caregiver of children
  • fleeing puts child at risk
  • study from rats - physiological response that inhibits stress by releasing oxytocin which decreases stress response in women
• limitation - negative consequences of fight or flight

  • stressors of modern life don't need such a physical response
  • when stress response is repeatedly activated, it can lead to physical damage - e.g. repeatedly raising blood pressure lead to heart disease
  • cortisol - dampens immune response - struggle to fight infection or heal damaged tissue
• strength - positive behaviours in stressful events

  • Von Dawans - challenge view that men response with F/F and women with tend + befriend
  • study found that acute stress can lead to friendly + cooperative behaviour - explains human connection in times of crisis, such as 9/11
  • could be the result of the protective nature of human social relationships that has allowed our species to thrive
• strength - genetic basis to sex differences in f/f

  • Lee and Harley - SRY gene found on Y chromosome promotes aggression and results in fight or flight as a response to stress
  • absence of SRY in females + action of oestrogen and oxytocin may prevent the stress response
• what is the difference between stress and a stressor?

  • stress = emotion we feel when perceived demands of a situation and our perceived ability to cope do not match
  • stressor = an event/situation that causes stress
• fight or flight is an automatic innate response