The Fight or Flight Response Flashcards
the fight or flight response
4
a sequence of activity within the body that is triggered when the body prepares itself to defend or attack (fight) OR run away to safety (flight)
involves changes in the nervous system and the secretion of hormones that are necessary to sustain arousal — e.g. the heart beats faster, breathing becomes more rapid and muscles tense
occurs when a person experiences a threatening or stressful situation, the fight or flight response is designed to help them deal with this situation
it has evolved as a survival mechanism to enable animals and humans to react quickly to life-threatening situations — bodily changes involved in the response allow us to fight off a threat of flee to safety
key features of the fight or flight response
8
amygdala
hypothalamus
sympathetic nervous system
adrenaline
parasympathetic nervous system
pituitary gland
adrenal glands
feedback system
amygdala and hypothalamus
5
when faced with a threat, an area of the brain called the amygdala is mobilised
the amygdala associates sensory signals (what we see, hear and smell) with emotions associated with fight or flight such as fear or anger, it then sends a distress signal to the hypothalamus
the hypothalamus functions like a command centre in the brain, it communicates with the rest of the body through the sympathetic nervous system
the body’s response to stressors involve 2 major systems; one for acute, sudden stressors such as a personal attack and the other for chronic, ongoing stressors such as a stressful job
very fast paced process, we usually aren’t aware of it and can react without thinking
response to acute stressors
3
involves the…
- sympathetic nervous system
- adrenaline
- parasympathetic nervous system
sympathetic nervous system
2
when faced with an acute stressor, the sympathetic nervous system is triggered and begins to prepare the body for rapid action necessary for fight or flight
it sends a signal to the adrenal medulla which responds by releasing the hormone adrenaline into the bloodstream
adrenaline
5
adrenaline circulates the body and causes physiological changes such as…
- an increase in heart rate which pushes blood faster to the muscles, heart and other vital organs
- an increase in blood pressure
- breathing may become more rapid to take in more oxygen with each breath
- may also trigger the release of glucose and fats which flood the bloodstream and supply energy to parts of the body associated with the fight or flight response
parasympathetic nervous system
4
when the threat has passed, the PNS dampens down the stress response
the SNS previously caused the heart to beat faster and blood pressure to increase, so now the PNS slows down the heartbeat and reduces blood pressure
this makes the body feel more relaxed and causes it to return to its normal state
it also causes digestion to begin again as it was previously inhibited by the SNS
response to chronic stressors
3
if the brain continues to perceive something as threatening, the second response system kicks in
as the initial surge of adrenaline subsides, the hypothalamus activates a stress response system called the HPA axis which involves the hypothalamus, pituitary gland and adrenal glands
key features of this system... • hypothalamus • pituitary gland • adrenal glands • feedback system
hypothalamus
2
the HPA axis relies on a series of hormonal signals to keep the SNS working
in response to a continued threat, the hypothalamus releases a chemical messenger called CRH (corticotrophic releasing hormone) into the bloodstream
pituitary gland
2
CRH arrives to the pituitary gland and causes it to produce and release ACTH (adrenocorticotrophic hormone)
ACTH is then transported to target sites in the adrenal glands via the bloodstream
adrenal glands
4
ACTH stimulates the adrenal cortex to release stress related hormones including cortisol
cortisol is responsible for several bodily effects that are important to the fight or flight response
some of these effects are positive such as a quick burst of energy and a lower sensitivity to pain
while others are negative such as impaired cognitive performance and a lowered immune response
the feedback system
4
very efficient at regulating itself
the hypothalamus and pituitary gland have special receptors that monitor circulating cortisol levels
if these levels rise above a certain amount, the hypothalamus and pituitary gland initiate a reduction in CRH and ACTH levels which bring cortisol levels back to normal
this is known as the feedback system
x3 evaluation points
fight or flight response may be different in women
the response has negative consequences
not a complete explanation
fight or flight response may be different in women
7
a limitation of the fight or flight response is the existence of challenging research
Taylor et al (2000) suggested that women actually respond differently to stress than men, they ‘tend and befriend’ rather than ‘fight or flight’
the tend and befriend response involves protecting themselves and their young through nurturing behaviours (tending) and forming protective alliances with other women (befriending)
Lee and Harley (2012) suggest this is due to the SRY gene, found exclusively on the male Y chromosome, which promotes aggression and may result in the fight or flight response to stress. the absence of the SRY gene in females, together with oestrogen and oxytocin, may prevent a fight or flight response to stress
women may have a completely different system for coping with stress because their responses evolved in the context of being the primary caregiver of their children, meaning they would not flee at any sign of danger as this would put their offspring at risk
perhaps the release of oxytocin increases relaxation, reduces fearfulness and decreases the stress response characteristic of the fight or flight response
therefore, if men and women have different stress responses, the fight or flight response may not provide an accurate explanation of how everyone reacts to stressful or threatening situations so should be viewed with caution
the response has negative consequences
6
a limitation of the fight or flight response is that it can have negative consequences
physiological responses associated with fight or flight tend to require energetic behaviours and actions, but the stressors of modern life rarely require such levels of physical activity
so a problem for modern humans arises when the stress response is repeatedly activated
for instance, the SNS involved in the fight or flight response increases blood pressure which can physically damage blood vessels and eventually lead to heart disease
similarly, too much cortisol suppresses the immune response which shuts down the very process that fights infection, leaving us vulnerable to illness
therefore, the fight or flight response can have very severe negative consequences for our health
