The Fight Or Flight Response Flashcards
What is the fight or flight response
A sequence of activity within the body that is triggered when the body prepares itself for defending or attacking (fight) or running away to safety (flight)
This activity involves changes in the nervous system and the secretion of hormones that are necessary to sustain arousal
What is the amygdala?
Associates sensory signals with emotions such as anger or fear and sends a distress signal to the hypothalamus
What is the hypothalamus
In response to continued threat it releases CRH into the bloodstream
Command centre in the brain
Communicates with the rest of the body through the SNS
What is involved in response to acute stressors
Sympathetic nervous system and adrenaline and PNS
What is involved in response to chronic stressors
HPA axis
What does the SNS do in response to stress
Begins the process of preparing the body for rapid action necessary for fight or flight
SNS sends a signal through to the adrenal medulla which responds by releasing the hormone adrenaline into the bloodstream
How is adrenaline involved in fight or flight
Causes a number of physiological changes: heart beats faster pushing blood to the muscles heart and other vital organs and blood pressure increases
Breathing becomes more rapid to take in as much oxygen as possible
Triggers the release of glucose and fats in the bloodstream which supply energy to parts of the body associated with fight or flight
What does the parasympathetic NS do
When threat has passed it dampens down the stress response
Slows down heartbeat and reduces blood pressure and digestion begins again
What is the HPA axis
Activated by the hypothalamus
A second system that kicks in if brain continues to perceive something as threatening
Consists of the hypothalamus, pituitary gland and adrenal glands
What is the pituitary gland
On arrival at the pituitary gland, CRH causes pituitary to produce and release ACTH.
This is transported in the bloodstream to its target site in the adrenal glands
What are the adrenal glands
ACTH stimulates the adrenal cortex to release various stress related hormones including cortisol
What is cortisol responsible for
Several effects in the body important for the fight or flight response
Some are positive - a quick burst of energy and low sensitivity to pain
Some are negative- impaired cognitive performance and lowered immune response
What is feedback
Both hypothalamus and pituitary gland have special receptors that monitor circulating cortisol levels
If these rise above normal they initiate a reduction in CRH and ACTH levels.
Bringing cortisol levels back to normal
