Stress as a bodily response...
TWO main ways our body responds to stress and both involve adrenal gland (2 sections of the gland - Adrenal cortex and adrenal medulla)
THE SYMPATHOMEDULLARY PATHWAY (short term)
the autonomic nervous system (ANS) role is to maintain the normal functioning of bodily systems in response to demands.
- sympathetic subdivision - when activated... heart rate and blood pressure increase, fats and carbs are mobilized, activity in digestive tract slows down = sympathetic arousal
- parasympathetic subdivision - when activated... heart rate and blood pressure return to normal and digestion speeds up.
The adrenal medulla is controlled by the ANS and activation of the sympathetic branch stimulates it to release the hormones adrenaline and noradrenaline.
TOGETHER the hormones reinforce the pattern of sympathetic activation = heart rate and blood pressure increased.
THE PITUITARY ADRENAL SYSTEM (long term)
- Under the contol of the hypothalamus and pituitary gland.
- Higher brain centres evaluate a situation as stressful, instructs hypothalamus to release CRF (corticotrophin releasing factor) which travels to pituitary gland.
- Pituitary gland releases the hormone ACTH.
- ACTH travels to adrenal cortex and stimulates the release of the hormones corticosteriods into the blood stream.
Activating the body's stress response...
The two systems, when aroused, prepare the body for energy expenditure. Corticosteriods, adrenaline and noradrenaline mobilize energy reserves and sustain blood flow and heart rate to get oxygen to the muscles.
The General Adaption Syndrome (GAS)
- Alarm - stress reponse = systems activated
could be a threat, injury, illness affecting body
- Resistance - body copes with stress
coping with the stressor, so from the outside it seems under control
- Exhaustion - stress-related illness may develop
if the stressor is long lasting/chronic then damaging effects of stress can occur.
'Fight or flight' or 'tend and befriend'…