The autonomic nervous system
Is central to homeostasis.
Homeostatis is a regulation of a constant internal enviroment. e.g. body temperature.
ANS has two separate divisions
the sympathetic branch - arousal (e.g. increase heart rate)
the parasympathetic branch - physiological calm (e.g. decrease heart rate)
Hypothalamic-pituitary -adrenal axis
Hypothalamus stimulates realse of
from pituitary gland into bloodstream
ACTH travels to cortex of adrenal gland and
triggers the realise of
cortisol and corticosteriods into bloodstream
The sympathetic-adrenomedullary (SAM) pathway
Activated by the hypothalamus,
nerve pathways of the
sympathetic branch of the
stimulates the adrenal medulla
to realise adrenaline and noradrenaline into the bloodstream
GAS Seyle's general adaption syndrome
Stage 1: Alarm
stressor perceived and HPA and SAM activated. Stress related hormones surge, heart rate and blood pressure increase.
Stage 2: Resistance
if stress presists body's response remains activated bodily arousal remain high.
Stage 3: Exhaustion
chronic stress eventually exhausts the body's defence system. This is when stress related illness may develop.
- Ignors individual differences and cognitive elements of perception and appraisal.
- it is thought that its the effect of the chronic raised levels of stress hormones that can lead to illness.
Other key points
Transactional model of stress: primary and secondary appraisal processes, we identify sources of stress in the enviroment and then assess our available coping resources. Stress exists when there is an imbalance between the two.
Modern stressors do not usually lead to "fight or flight" and we do not burn up the energy resources they may contribute to stress related illness.