PSY333H1 Lecture Notes - Lecture 5: Adrenal Medulla, Allostatic Load, Tachycardia
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July 20, 2011
Lecture 5 – Stress and Moderators of Stressful Experience
Stress
1.Usually a negative emotional experience
2.Predictable factors: biochemical, physiological, cognitive, and behavioral changes
3.Response can be directed either toward >>>>>>>>>>>>>>>
4.Stress has 2 main components
1.Physical - direct material or physical challenges
2.Psychological - how we perceive circumstances in our lives
5.3 ways of examining stress
1.Stress as a stimulus
i.Focusing on external environment
ii.Physical/psychological challenges = stressors
2.Stress as response
i.Focus on people's reactions
ii.Strain - physical (heart pounds, mouth dry) & psychological
(thought/emotion patterns) reactions
3.Stress as a process
i.Relationship between person and environment
ii.Transaction = continuous interactions and adjustments
iii.Person and environment each affecting and being affected by the other
6.Stress = the circumstance in which transactions lead a person to perceive a
discrepancy btw physical or psychological demands of a situation and the resources of
his or his bio, psycho, and social aspects
7.Stress is in the eye of the beholder
1. Individual differences are huge factor!
8.Perceptions of discrepancies between environmental demands and actual resources
1.Can be either real or just believed to exist
2.Stress is often results from inaccurate perceptions
Appraising events as Stressful
3.Assessment of whether personal resources are sufficient to meet the demands
of environ = cognitive appraisal
9.Mental processes involving 2 assessments:
1.Whether demand threatens physical or psychological well-being
2.Resources available for meeting the demand
Theories of Stress
10.Cannon's Fight-or-Flight response
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•Perceive threat >> Sympathetic & endocrine system >> prepares body
to attack or run
•Evolutionary advantage = Flee predators
•Today = withdrawal from drugs
•Adrenomedullary response - in response to stress the adrenal medulla will
release Norepinephrine and Epinephrine (catecholamines)
•Positive effects > fast response to danger
•Negative effects > prolonged arousal can be harmful to health
•Selye's General Adaptation Syndrome
•Canadian father of stress research
•Conducted mainly with rats exposed to different stressors
•Stress response for rats always stayed the same physiologically
•Called this series of physiological reactions the general adaptation
syndrome (GAS)
•GAS >> an andrenocortical response
•Glucocorticoids released from the adrenal cortex
•Physiological response
Enlarged adrenal cortex
Smaller thymus and lymph glands
•Important for immunity
Ulceration of the stomach and duodenum
•3 stages
Alarm Reaction
•Cannon's fight-or-flight response
•Fast-increasing arousal
•Results from the activation of hypothalamus-
pituitary-adrenal axis (HPA)
i.CRH (from hypothalamus) >> ACTH (from
anterior pituitary) >> cortisol (from adrenal cortex) >> sends
negative feedback back to hypothalamus
Stage of Resistance
•Strong stressor continues but is not severe
enough to cause death
•Body tries to adapt to stressor
i.Physiological arousal remains high
ii.Body replenishes adrenal hormones
•Impaired ability to resist stressors
i.Vulnerable to health problems (diseases of
adaptation)
ii.Ulcers, high BP, asthma, impaired immune
function
Stage of Exhaustion
•Resources are limited
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