Biopsychology(the fight or flight response) Flashcards
The Amygdala -
When faced with a threat this part of the brain is activated. It associates sensory signals (hear or see) with emotions associated with the fight or flight. (anger or fear). It send the distress signal to the hypothalamus.
The hypothalamus
Acts like a command centre in the brain, communicating with the rest of the body through the sympathetic nervous system. The body response to the stressors involve two major systems one for acute (sudden) stressors for personal attack. The second for chronic stressors such as a stressful job.
Acute stressors -
Sudden, like a personal attack
Chronic stressors -
Ongoing, such as a stressful job
Response to acute (sudden) stressors -
When Sympathetic NS is triggered, it prepares body for rapid action necessary for fight or flight. Sends a signal to the adrenal medulla which responds with the releasing of adrenaline.
Adrenaline - sudden stressors (acute)
Circulates the body for through the bloodstream. Causes psychological changes. Increased breathing, blood pressure, heart rate. Also triggers the release of glucose into the bloodstream and fats which supply energy to the parts of the body associated with fight or flight.
Parasympathetic nervous system - response to stressors (acute)
When the threat has passed the parasympathetic nervous system dampens down the stress unlike the sympathetic nervous system. It slows down heartbeat again with blood pressure. A benefit is that digestion begins again and is inhibited during the sympathetic nervous system.
Response to chronic stress (ongoing)
If the brain continues to perceive something as threatening the second response system comes in (activated by the hypothalamus). Called the HPA axis
HPA axis meaning -
H = Hypothalamus
P = Pituitary gland
A = Adrenal glands
The Hypothalamus in the HPA axis -
Relies on a series of normal hormonal signals to keep the SNS working. In the response to the continued threat, releases a chemical messenger called CRH which is released into the bloodstream to the stressor.
The pituitary gland in the HPA axis -
On arrival at the pituitary gland, CRH causes the pituitary to produce and release ACTH, from the pituitary gland ACTH is transported in the bloodstream to its target site in the adrenal glands.
The adrenal glands in the HPA axis -
ACTH stimulates the adrenal cortex to release various stress based hormones, including cortisol. Its responsible for several functions in the body which are important in fight or flight. Some are positive (lower sensitivity to pain) whereas others are negative (impaired cognitive performance)
Fight or flight does not tell the whole story -
Gray argues that the first phase of the reaction is to not fight or flee but is simply to freeze (freeze response). This response is an essential stop, look, listen response where the animal is alert to the slightest sense of danger. This may show adaptive advantages of this response for humans which may offer the most suitable approach for the individual. Freezing focuses attention on a particular threat to assess the and make the best response for a particular threat.
Genetic basis in behaviour of fight or flight response -
Lee and Harley found evidence of a genetic basis for gender differences in the fight or flight response. For example the SRY gene found exclusively on the male Y chromosome promotes aggression and results in the fight or flight response to stress. The SRY gene may prime males to stress in this way by the release of stress hormones such as adrenaline and through increased blood flow to organs involved in the response. Whereas, the absence of the SRY in females (who do not possess a Y chromosome) may present this response to stress, leading instead to tend and befriend behaviours.
