First 375 words of the document:
Stress and the immune system.
The immune system is what helps defend the body agaisnt antigens e.g. bacteria,viruses, toxins and parasites. It
defends the body in these ways 1) creates a barrier and stops them entering the body
1. if they do get in, the system tries to eliminate it.
There are two types of immunity: 1) b cells turn into a specific anitigen and when that antigen enters the body its
produce millions of specialised immune proteins called anti bodies to defend and kill it. This is TH2 immunity.
1. t cells are more aggressive cells. They bump up against the cell wall of the invading cell and destroy it and it
virus. This is TH1 immunity.
Stress can effect these two different types of branches as the different stressors use the different branches. For
example chronic usually uses TH2 immunity.
Kiecoltglaser et al carried out a natural experiment. She looked at the effect of short term stressors (exams) on
medical students and the immune system. She took blood sample 1 month before and during the stressor and
measured the nk cells activity to measure the immune system. Nk cell activity was seriously reduced during the
stressor compare to one month before the stresssor. This suggest short term stressor reduce the immune system
functioning and increases vulnerability to illness.
looked at how quickly wounds heal in those suffering chronic stress. She looked at two groups which she matched
participant wise. One was the experiment group which was a groups of female carers and the other group of non
carers matched on age and income. All participants were cut just below the elbow. Cytokine levels were measured
as it controls the immune system. The carers wounds took on average 9 days longer to heal than the control groups.
Cytokine levels were lower in carers. This shows stress weakens the immune system functions. Criticism of this
study is that they were not matched on marital status which would effect more or less stress. And they didn't
measure stress levels in carers in case they were suffering different levels of stress.