Slides in this set
The body's response to stress
Stress definition- When an imbalance or discrepancy exists
between perceived demands and perceived coping resources,
then a state of stress exists.
The autonomic nervous system (ANS)
Sympathetic branch- leads to pattern of bodily arousal which
increase heart rate, blood pressure, sweating etc. Sympathetic
arousal is an important part of the body's response to stress.
Parasympathetic branch- reverses the effects of the sympathetic
branch and leads to a pattern of physiological calm.…read more
The Sympathetic Hypothalamic-
(SAM) Pathway (HPA) Axis
Cortex recognises a stressor Stressor is recognised
Sends a message to the Message is sent to the
Activates the sympathetic Sends a message to the
branch of the autonomic pituitary gland
nervous system (ANS) Pituitary gland releases
This stimulates the adrenal ACTH
medulla Stimulates adrenal cortex
Adrenaline and noradrenalin Corticosteroids released
are released Immune system suppressed
Stress response is elicited e. and conversion of stored fat
g. Sweating, increased heart and protein into energy is
rate and blood pressure facilitated…read more
Selye's General Adaptation
Alarm- HPA axis and SAM pathway are activated. Levels of stress
related hormones surge. Heart rate and blood pressure increase.
Resistance- If stressor persists the response systems maintain
activation and hormone levels remain high.
Exhaustion- Long periods of stress exhaust defence systems .
Stress related illness may develop.
This is a response based approach to stress which ignore individual
differences and the elements of perception and appraisal.
Stress related illnesses are no longer thought to be caused by
exhaustion of the body's physiological stress responses.…read more
Stress and the immune system
Cohen et al (1993)
Investigated the role of general life stress on vulnerability
to the common cold virus.
Procedure- 394 participants completed stressful life events questionnaire
and rated their degree of stress and negative emotions to give an overall
stress index. Participants exposed to cold virus, 82% became infected and
development of cold was recorded.
Findings Life stress and negative emotions reduce the effectiveness of
the immune system so participants are less able to resist viral infections.
Ethical Issues- Scientific value of the study should be balanced against
psychological or physical distress to participants that may be caused. All
usual ethical issues apply e.g. Informed consent.
Methodological Issues- There were no direct measures of immune function.
There was no direct manipulation of the independent variable so cause
and effect relationship cannot be confirmed.…read more
Stress and the immune system
Kiecolt-Glaser et al (1984)
Investigated the level of natural killer cells in students at
different levels of stress.
Procedure- NK cell activity recorded in blood samples from students
one month before exams (low stress) and during exam season (high
stress). Questionnaires were also carried out by participants on
negative life event and social isolation.
Findings- Natural killer cell activity was significantly reduced in the high
stress samples. Stress reduces immune system function.
Ethical Issues- Must be approved by ethics committee due to small
wound caused. All usual ethical issues apply e.g. Full informed consent
must be given.
Methodological Issues- NK cells are a small part of a complex immune
system so a measure of their activity may not give the full picture.
There was no manipulation of the independent variable so cause and
effect cannot be confirmed.…read more