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STRESS 2:Stress and the Immune System

By M. Cardwell, amended by S. McGinnes

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The specification

Stress as a bodily response The body’s response to stress Stress-related illness and the immune system

Stress in everyday life Life changes and daily hassles Workplace stress Personality factors Psychological and biological methods of stress

management

Outline of Today’s Session

The immune system

Effect of stress

Effect of acute stress

Exam

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THE IMMUNE SYSTEM

Defends body against antigens (bacteria, viruses, toxins and parasites)

Cortisol suppresses immune system functioning

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Lymphocyte

A white blood cell generated by the immune system Defends against cancerous cells,

pathogens, and foreign matter Circulates in blood and lymph fluid

Three main types: T cells, B cells (specific immune

responses) Natural killer cells (non-specific)

Cytokines

“Cell signalling molecules” that control response to infection, inflammation, trauma, etc.

Some pro-inflammatory Initiate inflammatory response necessary to recruit

white blood cells to fight disease NB excessive inflammation can be harmful

Others anti-inflammatory Reduce inflammation, promote

healing once injury/infection/foreign body destroyed

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Natural Killer (NK) Cells

Small lymphocytes React against and destroy other cells

without prior sensitisation to them

Part of our first line of defence against cancer cells virus-infected cells

Attaches to target cell, releases chemicals that breach its cell wall, and causes it to lyse (break up)

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Stress and the immune system

Kiecolt-Glaser et al. (1984) natural killer (NK) cells in the blood of students taking exams.

How?

✴ Blood samples taken one month before exams (low stress) and during exams (high stress).

✴ Questionnaires assessed psychological variables e.g. life events.

Findings

✴ NK cell activity was significantly reduced in the second blood sample.

✴ Especially in participants reporting other significant life stressors.

Stress and the immune systemKiecolt-Glaser et al. (1995) compared female caring for relatives suffering from senile dementia with a matched control group.

How

All participants given a wound – a ‘punch biopsy’.

Cytokine levels were monitored.

Findings

Complete wound healing took longer in the carers than the controls.

Cytokine levels were higher.

Carers indicated on a perceived stress scale that they were feeling more stressed.

Acute stress may enhance the immune

system

Evans et al. (1994)

Antibody salivary IgA (sIgA) coats the mucous surfaces of the mouth, lungs and stomach, and helps protect against infection.

How? Arranged for students to give talks to

other students (mild stress).

Findings The students showed increase in sIgA. Whereas levels of sIgA decreased

during examination periods which stretched over several weeks.

• Stress appears to have two effects on the immune system:

• up-regulation for very short-term stress

• down- regulation for long-term stress.

• This fits the SAM/HPA distinction

Sandy and Vandita play for the same netball team. Two weeks ago, while playing in a competition, they both grazed their elbows. Vandita’s wound is healing well, but Sandy’s wound is taking much longer to heal. Sandy is very worried about the plans for her wedding and her forthcoming house move.

Using your knowledge of psychology, explain why Sandy’s wound is taking longer to heal than Vandita’s. (4 marks)

Jan 2010

Exam question

The exam

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What is meant by …. (3 marks)

Describe one research study that has investigated ….. (6 marks).

Describe and evaluate research … (6 marks + 6 marks)

3 studies /explanations3 evaluative

points