Week 5: Stress Flashcards
What is stress?
A NEGATIVE EMOTIONAL EXPERIENCE
Accompanied by predictable biochemical, physiological, cognitive and behavioural CHANGES
Directed at ALTERING stressful event
Or ACCOMMODATING to its effects
How does stress arise?
Primary appraisal > Labelling: What is this event? > Harm, threat, challenge?
+
Secondary appraisal > Can I respond to it? > Available and sufficient resources?
What are the models of stress?
- Fight-or-flight
- Selye’s general adaptation syndrome
- Tend-and-befriend
- Challenge vs. threat
What is fight-or-flight?
Walter Cannon (1932):
- When threat is perceived, body experiences AROUSAL via the activation of the SNS and endocrine system
- Which mobilises the organism to action
What is fight? What is flight?
Fight = aggressive response, flight = withdrawal
Is fight-or-flight good for us?
Adaptive b/c it helps org. to respond quickly
But repeated or unabated activation & arousal = health problems
What is Selye’s general adaptation syndrome?
Hans Selye (1956):
- All stressors elicit the same pattern of physiological changes.
- REPEATED or PROLONGED EXP. of these changes will exert wear and tear on system
What are the 3 stages of stress based on Selye’s general adaptation syndrome?
1) Alarm: Mobilised to meet the threat
2) Resistance: Tries to confront and/or cope with threat
3) Exhaustion: Depletion of physio. resources when efforts to overcome threat fail/succeeed
What are the criticisms of Selye’s general adaptation syndrome?
1) Assumes all stress lead to the SAME LEVEL of physio response; does not consider the role of appraisals (ignores indiv. diffs. in stress reactivity)
2) Assumes all stressors produce the SAME KINDS of biological responses; does not consider role of personality, emotions and biological constitutions (e.g. emotions - positive emotions also produce same kind of bio. response)
3) Unclear about what is most implicated in exp. of stress - exhaustion or chronic activation (resistance)?
4) Stress can occur before and persist after the duration of the stressor; it is not limited to the three phases – A) Stress may peak at another stage, B) Some ppl’s stress response do not decrease, actually remain sustained/persist after stressor
What is tend-and-befriend?
Taylor et al. (2000):
- Ppl and animals can respond to stress with SOCIAL AFFLIATION and NURTURANT BEHAVIOUR toward offspring, particularly for females
What is the concept behind tend-and-befriend?
Arises due to gender diffs. in adaptive challenges
Men = Hunting & protection roles = Fight/flight response Women = Foraging & child care roles = Tend & befriend
What is the key underlying biological mechanism of the tend-and-befriend model?
Oxytocin (stress hormone)
- Increases affiliative behaviours and calmness
- Particularly infl. by estrogen (–> females)
What is the limitation of the tend-and-befriend model?
Assumes that it is a female-exclusive response
What is the challenge vs. threat model?
Secondary appraisals of stressors can alter the experience and response to stressors
How does one determine whether a situation is a challenge or a threat?
Blascovich & Tomaka (1996):
- Secondary appraisals depend on the assessment or situational demands vs. personal resources
- PR > Sit. demands = Challenge, approach
- PR < Sit. demands = Threat, withdraw
How does challenge/threat appraisals affect cardiovascular profiles?
Challenge states: Short PEP, high CO, low TPR
Threat states: Short/long PEP, low CO, high TPR
What are the pathways to poor health due to stress?
1) Direct physiological effects
- E.g. elevated BP
2) Health behaviour changes
- E.g. increased smoking
3) Psychosocial resources
- E.g. threatened social support
4) Healthcare
- E.g. decreased adherence to treatment
What is the physiology of stress?
Sympathetic-Adreno-Medullary (SAM) system
- SNS
- Endocrine system
Hypothalamic-Pituitary-Adrenal (HPA) axis
- CNS
- Endocrine system
Primary & secondary appraisals of stressors are first performed by the cerebral cortex which then set off these responses
What is the process of activation of SAM system?
- Event appraised as stressful -> Brain sends info to HYPOTHALAMUS to activate SNS
- SNS activation -> Stimulates ADRENAL MEDULLA -> Secrete catecholamines
What are the effects of activation of SAM system on chronically stressed individuals?
- Suppressed immune system due to excessive release of EP and NE
- Higher risk of CVD due to overactive SNS
What is the process of activation of HPA axis?
- Event appraised as stressful -> HYPOTHALAMUS stimulates PITUITARY GLAND -> Secrete ADRENOCORTICOTROPIC HORMONE (ACTH)
- ACTH -> Stimulates ADRENAL CORTEX -> Release glucocorticoids, esp. CORTISOL
What are the effects of activation of HPA on chronically stressed individuals?
- Generally heightened cortisol levels (esp. awakening cortisol)
- Exaggerated cortisol reactivity, and slow recovery
What are the other considerations for the physiology of stress?
1) Reactivity
2) Recovery
3) Allostatic load
What is reactivity?
Degree of change (from baseline or average) that occurs in autonomic, neuroendocrine, and/or immune responses due to stress
Affected by genetic make-up, personality or early life exp