Slides in this set
The body's response
The stress response was important to ancestors because the bodily changes associated with stress were
essential for the `fight or flight' conditions which helped them deal with the current stressors. It has come
to mean a state of energised readiness. The body's response involves 2 major systems:
1) Acute Stress: SAM (sympathetic adrenal medullary):
Immediate stressors arouse autonomic nervous system (ANS) which is Pupils
divided into sympathetic branch (SNS) and parasympathetic branch. dilate =
Mouth goes dry
When the stressors detected, the hypothalamus is activated
Blood diverted from
SNS also activated digestive system
(butterflies) = more blood
for skeletal muscles Sweaty
Heart + breathing
This triggers response from adrenal medulla, which produces rate increased =
adrenaline & noradrenalin preparing body for fight/flight better blood flow
The parasympathetic branch then returns the body to its original state.…read more
2)Chronis stress: HPA (pituitary-adrenal system):
Then stressors are detected, the hypothalamus is activated which releases CRF as response.
This activates the pituitary gland which releases ACTH.
This activates the Adrenal Cortex which releases Cortisol,
responsible for suppressing the immune system.
It takes about 20 minutes for this to be complete and the Cortisol levels go above
average the pituitary glands and hypothalamus reduce them back to normal.…read more
Stress related illness: The immune system
The main function of immune system is to protect us from infectious agents. It can fail in 2
ways if it becomes: 1)under vigilant letting infections enter body causing illness 2)over
vigilant immune system attacks itself causing illness.
It protects you in 3 different ways: 1)creates barrier preventing antigens entering 2)if
antigen enters, immune system tries to eliminate 3)if virus is able to reproduce, immune
system aims to get rid.
One of the most important parts is the white blood cells (leucocytes) which are produced in
bone marrow, some remain there (known as B cells) and others migrate (know as T cells).
A specific B cell is turned into specific antigen producing millions of specialised antibodies
to fight it known as TH2 immunity. T cells detects harmful antigens and bump against to
destroy it, known as TH1 immunity. NK (natural killer) cells are important here and protect
against diseases like cancer. Cytokines are produced when 1 of these responses occurs to
prevent the other from activating maintaining a balance.
Kiecolt-Glaser et al (1984) - Natural experiment investigating whether stress of short term
stressor (exam) had an effect on immune system. He used 75 medical students and took
blood samples a month before and during exams and assessed NK cell levels as well as
giving questionnaires to assess any other variables. He found reduced NK cell level activity
in 2nd blood sample suggesting short term stressors do reduce immune cell functioning.
Marucha at al (1998) - took punch biopsy of mouth of students during summer holidays or 3
days before exams. It took 40% longer to heal in exam students than in holiday students.…read more
Kiecolt & Glaser et al (2005) found that wounds took longer to heal on a married couple who'
d had conflicting discussions than on those of supportive nature.
Malarkey et al (1994) - Investigated stress on the immune system and used 90 married couples
who were asked to talk about marital problems. After 24 hours, their urine sample was taken.
She found an increased amount of adrenaline/noradrenaline in their urine which can lead to poor
immune system functioning.
Boosting immune system:
Evans et al (1994) - Investigated effects of stress on the immune system looking at sIga
(antibody) in particular. Students were asked to give a presentation to their peers and they found
increased SIGA in the blood which proves strengthens the immune system. He suggested stress
can either up-regulation (acute) or down-regulation (chronic).
Segerstrom & Miller (2004) - conducted meta-analysis of 293 studies and found short term
stressors can boost immune system and long term stressors lead to suppression. The longer the
stress the more the immune system is shifts from adaptive to damaging.
Evaluation: Suggested by Lazarus (1992) that there are 3 reasons why a relationship between
stress & illness is difficult to establish:
1)Health is affected by multiple factors
2)Health is generally stable and slow to change so difficult to demonstrate exposure to particular
stressors causes change in health.
3)Impractical and expensive to demonstrate long term effects of long-term stressors.…read more
Stress related illness: Cardiovascular
Stress & Cardiovascular: Acute & chronic stress affect different aspects of the
cardiovascular system including hypertension (high blood pressure), CHD and strokes.
They're influenced by stress as well as lifestyle, diet and smoking. There are 2
explanations for why stress causes this:
1)Stress activates sympathetic branch leading to constriction of blood vessels & blood and
heart rate. 2)Increase in heart means the blood vessel lining wears away . Stress causes
higher glucose levels which means clumps can block blood vessels.
Card. Diseases & Anger (acute): A study conducted by Williams (2000) investigated if
heart disease and anger are linked. 13000 people completed 10 question anger scale, with
none suffering heart disease before experiment. 6 years on, 250 had. Those who scored
highest were 2.5x more susceptible (35%).
Card. Disease & work related stress (chronic): Medics were studied by Russek (1962)
and put into groups, either high stress (GP's) or low stress (pathologists). Heart disease
was higher in gp's (11.9% suffered) and lowest in dermatologists (3.2% of sample
Effects on existing conditions: Study by Sheps et al (2000) who focused on 173 men and
women volunteers who have ischemia (reduced blood flow to heart). They had to speak
publically, and blood pressure soared and in ½ sections of muscle began to beat erratically.
44% who had erratic heart beats died 3-4 years later compared to 18% who didn't. This
confirms stress can cause risk of death to people who have existing conditions.…read more