Fight-or-flight response

• There are two pathways involved in the body's response to stressors

  The SAM pathway and the HPA pathway
• The SAM pathway occurs as a result of acute, short-term stressors. In this stage, the body prepares itself for fight of flight.
• 1. Acute stressor is perceived by sensory input.
  2. Hypothalamus is alerted by the amygdala, activating the sympathomedullary pathway.
  3. This activates the sympathetic branch of the ANS which stimulates the activation of the adrenal medulla.
  4. The adrenal medulla secretes adrenaline and noradrenaline into the blood.
  5. Physiological changes occur: increased heart and breathing rate, inhibited metabolism, dilation of pupils and bronchi.
• To cope with long-term ongoing stressors, the body utilises the HPA pathway, which leads to the release of ACTH, a hormone which triggers the release of cortisol.
• • There may be differences in behavioural responses to stress in men and women.
  • Taylor suggests that women are more likely to adopt a ‘tend and befriend’ pattern - form protective alliances with other women.
  • However, researchers have challenged this, suggesting that acute stress leads to more positive cooperation in both.
  • Therefore this suggests that the protectiveness of human social groups allows our species to thrive - men and women’s stress responses are not completely different.
• • There is a genetic basis to sex differences in the ForF response.
  • The SRY gene, found only on the Y chromosome, directs male development which promotes aggression.
  • The gene may prime males to have this response to stress by release of adrenaline and other stress hormones in great amounts, increasing blood flow and heart rate.
  • In contrast, the absence of the SRY gene in females may actually prevent this type of response, rather leading to the original concept of tend and befriend.
• • There is some criticism for oversimplicity of the explanation.
  • Gray suggests that the first phase of ForF is actually avoiding confrontation with the threat rather than fighting or fleeing.
  • He suggests that before this, humans and animals display a ‘freezing’ response - hyperawareness of their surroundings, alert to the slightest sign of danger.
  • The adaptive advantage of this is that humans can focus on the stressor, allowing them to gain more information in order to make the best response to that particular threat.