04 stress and immune system 2010

8/3/2019 04 Stress and Immune System 2010

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2/18

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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5/18

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)


10/18

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?


18/18

Describe and evaluate research findings into

the link between stress, illness and the

immune system.

04 stress and immune system 2010

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