The immune system is a collection of billions of cells that travel through the bloodstream. They move in and out of tissues and organs defending the body against foreign bodies (antigens). There are two types of lymphocytes…
B cells… these produce antibodies which are released into the fluid surrounding the body’s cells to destroy the invading viruses and bacteria.
T cells… if the invader gets inside a cell; these (T cells) lock on to the infected cell, multiply and destroy it.
The main types of immune cells are white blood cells. There are two types of white blood cells – lymphocytes and phagocytes.
Some factors have suggested that stress can cause a deficient immune system. When we are stressed, the immune system’s ability to fight off antigens is reduced. This is why we are more prone to infections. Stress can also have an indirect effect on the immune system as a person may use unhealthy coping strategies to reduce their stress, such as drinking and smoking. Stress is linked to headaches, infectious illness (e.g. flu), cardiovascular disease, diabetes, asthma and ulcers.
Kiecolt-Glaser et al., (1984)
She investigated whether stress of important examinations has an effect on the functioning of the immune system.
The method she used…
- It was a natural experiment. They took blood samples from 75 first year medical students.
- The blood samples taken were: (a) one month before their final examinations (low stress), and (b) during the examinations (high stress)
- Immune functioning was assessed by measuring T cell activity in the blood samples.
- The students were given questionnaires to assess variables such as life events and loneliness.
What she found was that the blood samples which were taken from the first group (before the exam) contained more t-cells compared with blood samples taken during the exams. She also found that the greatest