The Fight or Flight Response (AQA GCSE Psychology)
Revision Note
Written by: Claire Neeson
Reviewed by: Lucy Vinson
The role of adrenaline
During situations that produce stress, fear or excitement, the neurons of the sympathetic nervous system (within the autonomic nervous system) stimulate the adrenal medulla (the inner part of the adrenal gland) to secrete adrenaline
Adrenaline is a hormone that prepares the body to deal with a fear/stress/excitement-inducing stimulus e.g. ‘I heard a noise downstairs!’
This reaction is often called the ‘fight or flight’ response i.e. stay and face the danger or run away quickly!
When a ‘danger’ signal is detected by the senses the first action of the adrenal glands is to release adenosine triphosphate, an energy-storing molecule that provides a short-lived, intense surge of power, designed to move you quickly out of danger’s way
Since adrenaline is a hormone, it is transported around the body in the bloodstream
Physiological changes in the fight or flight response to a threat
Physiological changes brought about by the fight or flight response include:
increased heart rate
dry mouth
increased sweating
dilated pupils
increased breathing rate
An increase in heart rate is required to supply blood to the muscles
More blood means more oxygen and glucose are needed which in turn increases the rate of aerobic respiration to release energy
Thus energy that could be used during the response to the stressful or dangerous situation is available
Blood vessels to less important organs (such as the digestive system and skin) constrict so that more blood can be diverted to organs that will be involved in the "fight or flight" response
Note that blood flow to the brain remains constant, regardless of whether the body is in a state of stress or relaxation
The brain is one of the most important organs in the body and needs a constant blood supply to function properly
Once the threat/danger has passed it is possible that someone may feel exhausted, sick or ravenously hungry due to the energy that has been released during the response
If this energy is not used via exercise/action then it can ‘sit’ in the body, possibly leading to stress and other long-term health conditions e.g. someone with high anxiety is probably living in a constant state of fight or flight
Examiner Tips and Tricks
An exam question may well ask you about the process of fight or flight or the physiological effects so make sure you are confident about each of these topics in Brain & Neuropsychology.
Worked Example
Here is an example of a question you might be asked on this topic - for AO2.
AO2: You need to apply your knowledge and understanding, usually referring to the ‘stem’ in order to do so (the stem is the example given before the question)
After each featured question there is a ‘model’ answer i.e. one which would achieve top marks in the exam.
Imagine that one morning as you are walking along the pavement, a dog comes racing at you from a nearby house, its teeth bared. The owner runs out of the house and gets hold of the dog before it attacks you. As you carry on walking, you realise that your mouth is very dry, you are sweating and your breathing and heartbeat are both very fast.
Question: Using your knowledge of the nervous system, explain why you are likely to be experiencing the described physical effects. [4]
Model answer:
It is likely that I am experiencing the fight or flight response. This is an automatic response to a real or perceived threat – like almost being bitten by an out-of-control dog!
My autonomic nervous system has reacted to the threat of nearly being bitten by switching from parasympathetic activity to sympathetic activity i.e. from relaxation to action. There is now adrenaline being released into my bloodstream.
When this happens, a number of changes take place physically – I breathe more quickly and my heart rate increases so that I have more oxygen in my blood and I am sweating to cool down my muscles. These are all so that I can run away from the danger – the out-of-control dog.
My mouth is dry because in the sympathetic state, I don’t produce saliva – because eating is definitely not important when faced with something that might take a chunk out of me!
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