Fight or Flight*

• The fight or flight response involves our autonomic nervous system, which is central to homeostasis (internal regulation). It has two separate divisions - the sympathetic and parasympathetic branch - which are usually in balance. When a stressor is perceived, the brain activates the sympathomedullary pathway which causes physiological changes in the body to help us cope with the situation which is known as the fight or flight response.
• Within the sysmpathomedullary pathway, the stressor is perceieved and the threat level is assessed. Then the hypothalamus activates the sympathetic branch of the autonomic nervous system. Sympathetic nerves then transmit the signals from the CNS to the adrenal glands. The adrenal medulla then releases adrenaline and noradrenaline into the bloodstream and the adrenaline constricts blood vessels in the skin to divert blood to the muscles.
• Adrenal glands are located at the top of each kidney and each section of the adrenal gland secretes a variety of different hormones. The adrenal cortex secrets cortisol and the adrenal medulla secretes adrenaline. Both cortisol and adrenaline are involved in the body's stress response.
• Adrenaline increases the heart rate to pump more blood and oxygen around the body and increase blood flow
• Adrenaline increases blood glucose levels to allow for more respiration
• Adrenaline increases pupil size to let more light into the eye to improve perception of the stressor
• Once the threat of a stressor has gone, the autonomic nervous system switches from the activation of the sympathetic branch to the parasymapathetic branch. This reduces the release of adrenaline into the bloodstream and has a calming effect on the body. This is known as the 'rest and digest response' and causes a decrease in heart rate and the return of digestive processes. Parasympathetic activation returns the body to a balanced state known as homeostasis
• A weakness of our understanding of fight or flight is that human behaviour is not limited to two responses during threatening situations. Gray argued that the first response to danger is often to 'freeze'. During the 'freeze' response, humans are hyper-vigilant and assess the situation carefully to decide on the best course of action....
• (Weakness is that human behaviour isn't limited to two responses) ....This suggests that the fight or flight response is too restrictive in its explanation of the behavioural response to threats and cannot fully explain the range of cognitive and biological influences on these behaviours. This shows that research into fight or flight is incomplete and reduces the validity of out understanding.
• A strength of our understanding of the fight or flight response is that the supporting evidence uses scientific methodology. Fight or flight research operationalises arousal through levels of hormones which is an objective measure that is free from researcher bias. The research investigating the physiological and behavioural processes involved in fight or flight is also usually carried out in controlled conditions that mean the methods can easily be replicated....
• (Strength is that evidence uses scientific methodology) ....This allows researchers to test the reliability of findings for both the physical and behavioural responses during fight or flight. This increases the validity of the research into fight or flight and the validity of our understanding