6. Stress and health Flashcards
Stress response
A non-specific response of the body to any demand that is placed upon it
(physical or psychological)
What did Selye say about stress?
All stressors evoke the same core physiological responses
- Mobilise the body for action
- sympathetic effects
- Mobilise energy resources
What are the 2 faces of stress responses?
Short term – adaptive
Longer term – maladaptive
What does psychological stress lead to?
Poor health outcomes
What is Selye’s original model of stress responses?
Initial response to stress (alarm reaction) → Adaptation stage (short term response to temporary stress) → if stress continues (chronic stress) → exhaustion phase
What are the implications of chronic stress?
Chronic stress & associated physiological changes (e.g. enlarged adrenal glands) are implicated in ill health
Acute stress
Adaptive processes; necessary to maintain homeostasis and adapt to environment
Chronic stress
Allostatic load
Negative effect on physical and mental health
Depletes energy reserves, comprises immune system
Allostatic load
Results from excessive stress or failure to achieve homeostasis, as a result of repeated stress from multiple stressors, poor adaptation and prolonged or inadequate responses to stress (McEwen, 2007)
What is the two-system view of stress and health?
Anterior-pituitary-adrenal-cortex system
sympathetic nervous system
What is the Anterior-pituitary-adrenal-cortex system of stress?
Stress → brain → anterior pituitary gland releases ACTH → adrenal cortex releases glucocorticoids (e.g. cortisol) → stimulates the effect of stress response
How is the sympathetic nervous system affected by stress?
Adrenal medulla → increases the release of adrenalin & noradrenalin
What is involved in the autonomic nervous system?
Sympathetic and parasympathetic responses
Sympathetic nervous system
- fight or flight
- enhanced heart rate, BP, RR, blood to muscles, dilate pupils, mobilised energy stores
- Adrenaline & noradrenaline (from adrenal medulla)
Parasympathetic nervous system
- decreased functions of heart rate, blood pressure
- insufficient evidence that individual emotions are characterised by different patterns of physiological response (but not al the same either)
In Selye’s original model – How do we measure stress?
The most commonly employed physiological measure of stress is the level of circulating glucocorticoids.
What is the developmental programming of the HPA axis?
Early stressful and nurturing environments – robust effects on the developing brain
The first few weeks of life represent a critical period – the HPA axis programing in rodents
As adults, offspring of “High quality maternal care” show less fearful behaviour and reduced HPA response to stress compared to offspring received “low quality maternal care”
(Liu et al., 1997; Caldji et al., 1998)
Neonatal handling vs. maternal separation experiment:
What is the handling procedure and what does it result in?
Neonatal pups received 15 minutes handling daily during postnatal days 2-14
Handling results in pups receiving increased maternal care (licking & grooming behaviour)
Thus, high maternal care (handling) lead to less stress and decreased HPA activity
Neonatal handling vs. maternal separation experiment:
What is the effect of maternal separation?
When there has maternal separation, neonatal pups are separated from the mother for prolonged period of time (several hours)
Maternal separation results in pups receiving less maternal care .
Thus, low maternal care (maternal separation) results in enhance stress and increased HPA activity
What was examined in the Romanian orphanage study?
The time of change in environment is important.