STRESS 2: Stress and the Immune System

1. STRESS 2: Stress and the Immune System By M. Cardwell, amended by S. McGinnes

2. 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

3. Outline of Today’s Session • The immune system • Effect of stress • Effect of acute stress • Exam

4. THE IMMUNE SYSTEM Defends body against antigens (bacteria, viruses, toxins and parasites) Cortisol suppresses immune system functioning

5. 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)

6. 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

7. 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)

8. Stress and the immune system • 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. Kiecolt-Glaser et al. (1984)natural killer (NK) cells in the blood of students taking exams.

9. Stress and the immune system Kiecolt-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.

10. 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

11. Exam question 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

12. The exam 3 studies /explanations 3 evaluative points