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8/3/2019 04 Stress and Immune System 2010
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Define the word stressor.
Give an example for each of the following:
Acute time-limited stressor Brief naturalistic stressor
Chronic stressor
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Explain what is meant by the immune
system
Describe how the immune system is affectedby the stress response
Outline and evaluate research into the effect
of stress on the immune system
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Destroys pathogens (definition: .........) and
cancer cells
Several types of _____ blood cell: Phagocytes eat pathogens
B Lymphocytes make anti____
Some T Lymphocytes kill infected cells, othersrelease cyto____ chemical signals in the bloodthat make the other parts of the immune systemdo their job
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1. Phagocytes2. Lymphocytesa) B-cellsb) T-cells
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Immune system
Pathogen
White blood cell Phagocyte
B Lymphocyte
Antibody
T helper cell
Cytokine
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1. Bodys resources are depleted (GAS model)
so proteins for immune system cannot bemanufactured.
Or2. Cortisol directly suppresses immune
system by decreasing production oflymphocytes, antibodies and cytokines.
How can we test which is true?
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Effects of stress on the immune system
Kiecolt-Glaser et al. (1995)
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To demonstrate the direct effects of stresson the immune system by looking at how
fast wounds healed in women experiencinghigh levels of chronic stress.
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Experimental group: 13women caring for relativeswith senile dementia, matched (age and income
but not marital status) with control group. All participants given a 3.5mm puncture wound on
arm, which was treated by a nurse.
Levels ofcytokines (hormones controlling immune
system) were assessed to measure immunesystem activity, and stress questionnaire used.
This is a natural experiment because
T
he IV and DV are
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Complete wound healing took on average 9days - 24% - longer in carers.
Cytokine levels were lower in carers. Carers indicated they felt more stressed.
These three different measures were used
because The conclusion of this study is
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Shows that chronic stress depressesfunctioning of the immune system both in
terms of healing and actual immune systemactivity.
Lower cytokine levels suggest a direct effect
of stress on immune system activity.
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(1) Important application to medicaltreatment e.g. people recovering from
surgery. (2) Sample bias more married women in
experimental group though they should
have better immune functioning (or shouldthey?).
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Aim: carers, chronic, wound healing
Procedure: carer group & control, puncture
wound, questionnaire, cytokines, healing Findings: 24% longer healing, cytokines low,
higher stress score
Conclusions: direct effect, immune system
and healing
Criticism: important in medicine, marital
status bias?
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What is a meta-review or meta-analysis?
How can we evaluate research into stress and
the immune system? What are the general conclusions that can be
drawn from several studies?
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In what ways is the Cohen et al study superior
to Kiecolt-Glasers medical student study?
In what ways is it less convincing? Are the ethical issues different?
Taking these two together, with K-Gs would-healing study, what can we conclude?
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Describe and evaluate research findings into
the link between stress, illness and the
immune system.