the fight or flight response

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 or running away to safety

how does the amyglada work in fight or flight?

it associates sensory signals with emotions associated with fight or flight, then sends a distress signal to the hypothalamus

what two major systems are involved in the body’s response to stress?

one for acute & one for chronic stressors

what does the hypothalamus act as?

a command centre in the brain, communicating with the rest of the body through the sympathetic nervous system

what is an acute stressor?

a sudden stressor

what does the SNS do when triggered?

sends a signal to the adrenal medulla

how does the adrenal medulla respond to the SNS’s signal?

releases adrenaline

what changes to the body does adrenaline cause?

• heart beats faster

• blood pressure increases

• breath rate increases

• blood sugar releases

what happens when the threat has passed?

the parasympathetic nervous system dampens the stress response

what happens if the threat is continued?

the adrenaline subsides and the hypothalamus activates the HPA axis

what is the HPA axis?

the sequence of bodily activity in response to stress that involves the hypothalamus, pituitary and adrenal cortex

what happens in the hypothalamus in the HPA axis?

releases CRH in response to the stressor

what happens in the pituitary gland in the HPA axis?

CRH arrives and causes it to produce & release ACTH which is transported to the adrenal glands

what happens in the adrenal glands in the HPA axis?

ACTH stimulates it to release stress-related hormones, including cortisol

what effects does cortisol have on the body?

POSITIVE

• quick burst of energy

• lower sensitivity to pain

NEGATIVE

• impaired cognitive performance

• lowered immune response

how does the HPA axis regulate itself?

cortisol levels are monitored by the hypothalamus and pituitary glands so that CRH and ACTH production is inhibited if too high

evaluation

• women may have a tend & befriend response rather than fight or flight - genetic basis

• physiological changes in fight or flight are not necessary in modern life

• does not include the initial reaction of avoiding confrontation

• acute stress can lead to greater cooperation & friendliness