The fight or flight response, including the role of adrenaline Flashcards
what is the fight or flight response
The fight or flight response is thought to be an innate, evolutionary-determined response to threatening situations
what is the hypothalamus
The hypothalamus lies at the base of the brain.
It is involved in many of the body’s physiological functions, such as stress-related arousal, hunger, thirst and sexual and reproductive behaviours.
It regulates many of these functions automatically.
If the cortex and limbic system identify a stressful situation of threat or danger, then the hypothalamus is stimulated to activate the sympathomedullary pathway.
The Fight or Flight Response: Acute stress and the Sympathomedullary pathway
Immediate (acute) stressors arouse the autonomic nervous system (ANS).
It is called autonomic because it governs itself i.e. heart beat, blood pressure, body temperature.
The ANS governs the release of hormones (chemical substances which circulate in the blood).
The Autonomic Nervous System (ANS
ANS centres are located in the brainstem. Pathways run down the spinal cord and are distributed throughout the body by spinal nerves.
It has two separate divisions: the sympathetic branch and the parasympathetic branch.
Nerve fibres from both branches connect with internal structures such as various glands e.g. the adrenal medulla.
The SYMPATHOMEDULLARY PATHWAY
Hypothalamus detects stressor/threat
Arousal of the Autonomic Nervous System (ANS) (Sympathetic branch)
SNS stimulates the Adrenal Medulla
…which releases Adrenaline and Noradrenaline
Release of adrenaline results in…..
Sweatiness
Increased heart rate and raised blood pressure
Diverts blood away from the skin
Breathing quickens and becomes shallower
Increases blood supply/oxygen to the brain (for rapid response planning) and skeletal muscles (for physical action)
Pupil dilation
Digestion slows down, to conserve resources for fight/flight.
Adrenaline also triggers….
the release of blood sugar (glucose) and fats into the bloodstream, supplying energy to the muscles to enable the individual to fight or flee the threatening situation.
Rest and Digest
The parasympathetic branch of the ANS returns heart rate and blood pressure to normal, as well as speeding up digestion, helping the body to relax.
However, some researchers challenge the view that men respond to stress or threats solely with the fight or flight response.
Von Dawans et al. (2012) found that acute stress can actually lead to greater cooperative and friendly behaviour, even in men. This could explain the camaraderie seen during times of crisis e.g. in the aftermath of 9/11.
It may be the case that stress leads to more cooperative behaviour because humans are social animals and they instinctively form bonds when faced with a threat, therefore giving a greater chance of survival.
It may be the case that females do not respond to threats in the same way as males.
Taylor et al. (2000) suggest that for females, behavioural responses to stress are more characterised by a pattern of ‘tend and befriend’ than ‘fight or flight’.
This involves protecting themselves and their young (perhaps because they are the primary caregiver) through nurturing behaviours (tending) and forming protective alliances with other women (befriending).
Fleeing too readily at any sign of danger would put a female’s offspring at risk.
The fight or flight response can also be criticised for being reductionist…
The fight or flight response could be seen as reductionist because it focuses on the physical response to stress, reducing stress responses down to purely biological processes.
This is a criticism because it overlooks psychological and social factors.
However, due to the physical nature of bodily systems the majority of the research that supports the fight or flight response can be deemed scientific, as the measures used to investigate are objective (e.g. measuring hormone levels in the blood) and as such accurate and reliable, therefore lending weight to the theory.
what is reductionism
Reductionism is the belief that human behaviour can be explained by breaking it down into smaller component parts.
