Fight or Flight Response Flashcards
What does the fight or flight mechanism allow an idividual to do
Fight off the threat or flee to safety
What happens when an individual is faced with a threat
The amygdala is mobilised, which associates sensory signals with emotions associated with fight or flight, such as fear or anger, and sends a stress signal to the hypothalamus, which acts as a command centre
What are the two types of stressors
Acute stressors (sudden), such as personal attack
Chronic stressors (ongoing), such as a stressful job
What is the response to acute stressors
The sympathetic nervous system is activated. This sends a signal to the adrenal medulla, which releases adrenaline into the bloodstream
What physical changes does adrenaline cause
-Faster Heartbeat, which pushes blood to muscles and vital organs, increasing blood pressure
-Breathing becomes more rapid in order to take in more oxygen
-A release in blood sugar and fats, supplying energy to the body
What happens in the response to acute stressors after a threat has passed
The parasympathetic nervous system is triggered, which dampens stress response by slowing down the heartbeat, reducing blood pressure. Digestion, which is inhibited when the sympathetic nervous system is activated, also begins again
What is the response to chronic stressors
As an initial urge of adrenaline subsides, the hypothalamus activates a stress response system called the HPA axis
What is the HPA axis
Consists of the hypothalamus, the pituitary gland and the adrenal gland. The hypothalamus releases corticotrophin-releasing hormone into the bloodstream. On arrival to the pituitary gland, it causes the production and release of adrenocorticotrophic hormone. This arrives through the bloodstream at the adrenal glands. ACTH stimulates the adrenal cortex to release stress related hormones like cortisol
What does the hypothalamus do in the HPA axis
Releases corticotrophin-releasing hormone, targeting the pituitary gland
What does the pituitary gland do as part of the HPA axis
When detecting CRH, it produces and releases adrenocorticotrophic hormone, targeting the adrenal glands
What do the adrenal glands do as part of the HPA axis
When stimulated by ACTH, the adrenal cortex releases various stress related hormones like cortisol
What does cortisol do to the body
Has some positive effects like a quick burst of energy and lower sensitivity to pain, while some effects are negative, such as impaired cognitive performance and lowered immune response
How is the chronic stress response in the Fight or Flight response regulated
The system is self-regulating, with both the hypothalamus and pituitary gland having special receptors that monitor circulating cortisol levels, and initiate a reduction in CRH and ACTH levels if they rise above a normal level, bringing cortisol levels back to normal
Why might the fight or flight response be gender biased
Taylor et al suggested that for females stress response are characterised by a pattern of tend and befriend rather than fight ot flight. This involves protecting their young through nurturing behaviours, which is tend, and forming alliances with other women, which is befriend. This may have evolved in the context of being the primary caregiver, so fleeing from danger would put a female’s offspring at risk. This is beta bias
Who suggested the tend and befriend response
Taylor et al
Why might there be a genetic basis to sex differences in the fight or flight repsonse
Lee and Harley suggested the SRY gene, found exclusively in the male Y chromosome, which directs male development, may be related to the fight or flight response. It promotes aggression and so may result in a fight or flight response to stress. The absence of the gene in females may prevent this response to stress. Higher levels of the hormone oxytocin in females could contribute to differing stress responses
Who suggested the genetic basis for differences in the fight or flight response
Lee and Harley
Why might the fight or flight response not be the whole story
Gray argued that the first phrase of reaction to a threat is to try and avoid confrontation. He suggests that prior to the other responses there is typically a freeze response. This is essentially a stop, look and listen response, where the animal is hypervigilant and alert to the slightest sign of danger. This has many adaptive advantages, for example, determining the best response to a threat
Who suggested that the fight or flight response is incomplete
Gray
What has challenged the view that under stress men respond only with fight or flight
Von Dawans et al’s study found that acute stress can actually lead to greater cooperative and friendly behaviour in both men and women. This could explain the human connection that happens during times of crisis. One possible reason for this behaviour is that humans are social animals and there is a protective nature of human social relationships that allowed our species to thrive
Who’s study suggests that both men and women get along in stressful situations
Von Dawans et al’s study
