Stress Flashcards
What is general adaptation syndrome?
Selye’s explanation of how the body responds in the same way to any stressor.
The response goes through three stages which are alarm reaction, resistance and exhaustion.
What does HPA stand for?
Hypothalamic-pituitary-adrenal system
What is HPA?
This controls how the body responds to a chronic stressor.
The hypothalamus triggers the pituitary gland to release the hormone ACTH which, in turn, stimulates the release of cortisol.
What is the SAM pathway?
This controls how the body initially responds to an acute stressor.
The sympathetic nervous system triggers the flight or fight response.
This includes the release of the hormones adrenaline and noradrenaline which communicate with target organs in the body such as the heart.
Where is cortisol produced?
Adrenal cortex
What does cortisol do?
It helps the body to cope with stressors by controlling how the body uses energy.
It also supresses immune system activity.
How did Selye (1963) view stress?
As the body’s attempt to adapt to a stressor.
This adaptation protects the body but is dangerous if the stressor is prolonged.
The process of adapting to a stressor goes through three stages which Selye called the general adaptation syndrome.
What are the three steps of GAS?
Alarm reaction- immediate physiological response.
Resistance- body attempts to adapt to stressful situation and physiological activity is greater than normal so after time the PNS is activated to conserve energy.
Exhaustion- Adaptation to the chronic stressor is failing so individual experiences symptions of the alarm reaction . This can damage the adrenal glands and compromise the immune system.
Research support of GAS.
Selye subjected rats to various physical stressors.
He found the same collection of responses occured regardless of the stressor and the response appeared after 6-48 hours.
Selye could also track the rats’ continuing reponses through the resistance and exhaustion stages.
A limitation of GAS.
Mason (1971) replicated Selye’s procedures using monkeys measuring response to seven different stressors by measuring levels of urinary cortisol.
Mason found outcomes depended on the stressor.
This challenges the validity of the GAS.
What is acute stress associated with?
The SAM pathway.
What happens during the SAM pathway?
When a stressor is perceived, the hypothalamus activates the sympathetic branch of the autonomic nervous system.
The arousal stimulates the adrenal medulla to produce adrenaline and noradrenaline.
This causes physiological responses.
What are some physiological responses to acute stress?
Turning glycogen into glucose.
Sweating.
Pupil dilation.
Increased heart rate.
Slowed digestion.
When does the sympathetic response to stress end?
When the stress becomes chronic or the parasympathetic nervous system takes over.
What is the body’s response to chronic stress?
HPA system.
Does the HPA take longer to activate than the SAM pathway?
Yes but also lasts for longer.
How does the HPA work?
When the sympathetic nervous system is activated, the hypothalamus also produces a hormone called CRF.
CRF is detected by the anterior lobe of the pituitary gland causing the release of ACTH into the bloodstream.
ACTH levels are detected by the adrenal cortex which secretes cortisol in response.
What does CRF stand for?
Corticotropin releasing factor.
What does cortisol do?
Helps the body cope with stress.
It is glucocorticoid because it affects glucose metabolism by mobilising and restoring energy supplies to power the stress response.
It has other effects which can be damaging to the body such as suppressing the immune system.
Is HPA a negative feedback loop?
Yes.
Levels of cortisol circulating in the bloodstream are monitored back at the pituitary and the hypothalamus.
High levels of cortisol trigger a reduction in both CRF and ACTH, resulting in a corresponding reduction in cortisol.
Real world application of the physiology of stress.
Knowledge of it has practical value.
Addison’s disease is a rare disorder of the adrenal glands, meaning people cannot produce cortisol- this means they cannot mobilise energy to deal with stress.
The lack of cortisol can trigger life threatening symptoms such as severe drops in blood pressure.
This knowledge has revolutionised treatment.
Now people with it can self administer daily cortisol replacement therapy.
Therefore the understanding of the physiology of stress has improved some peoples lives.
A limitation of the physiology of stress.
Physiological explanations ignore psychological factors in stress, for example cognitive appraisal.
Speisman et al. (1964) asked students to watch a medical procedure on film while their heart rates were measured.
Changes in heart rate depended on how the students interpreted what was happening in the film.
If they believed the procedure was traumatic their heart rate increased but if they were told it was voluntary, heart rates decreased.
This finding cannot purely be explained by physiology.
Gender bias of the physiological response.
Fight or flight is regarded as the universal response to an acute stressor.
That understanding is based on research of males and avoiding females due to hormone fluctuations.
However, Taylor et al. (2000) argue that the most adaptive stress response in females is ‘tend and befriend’.
It was adaptive for ancestral females to respond to stress by nurturing offspring and co-operating with other females.
The hormone oxytocin inhibits the fight or flight response in females some of the time.
How does cortisol affect the immune system?
Cortisol inhibits the production of lymphocytes.
What is immunosuppression?
Stress can cause illness by preventing the immune system from working efficiently and carrying out its usual task of identifying and destroying invading germs and other foreign bodies.
What are cardiovascular disorders?
Any disorder of the heart or blood vessels including events which affect the brain.
What did Kiecolt-Glaser investigate?
The affect of stress in immunosuppression.
What was Kiecolt-Glaser et al. (1984)- procedure?
Investigates the effects off exams on 75 medical students.
The participants gave blood samples twice, one month before an exam period and on the day of the first exam.
They also completed questionnaires measuring sources of stress and self-reported psychological symptoms.
What was Kiecolt-Glaser et al. (1984)- findings?
The researchers found that the activity of the NK and killer T cells decreased between the first and second samples, evidence of an immune response being suppressed by a chronic stressor.
This decline was most apparent in students who reported feeling most lonely and in those experiencing other sources of stress such as significant events in their life.
What was Kiecolt-Glaser et al. (1991)- procedure?
Carried out another longitudinal study in which they compared the health of two groups of people- caregivers looking after a relative with Alzheimer’s disease, and a matched group of non-caregivers.
What was Kiecolt-Glaser et al. (1991)- results?
Over a period of 13 months, the caregivers showed a weaker cell-based immune response.
There was no such increase in the control participants.
The caregivers also had infectious illnesses on significantly more days, and higher levels of depression with 32% meeting the criteria for the clinical depression (only 6% in the control group).
Who conducted acute stress research and its effect on cardiovascular disorders?
Wilbert-Lampen et al. (2008)
Who conducted chronic stress research and its effect on cardiovascular disorders?
Yusuf et al. (2004)
What was Wilbert-Lampen et al. (2008) procedure?
They looked at incidences if heart attacks in German football supporters during matches played during the 1996 world cup.
What was Wilbert-Lampen et al. (2008) results?
On the days when Germany played, cardiac emergencies increased by 2.66 times compared with a control period.
It appears that the acute emotional stress of watching your favourite football team can more than double your risk of experiencing a cardiovascular event.
What was Yusuf et al. (2004) procedure?
Examined chronic stressors in the INTERHEART study.
This involved 52 countries, to identify major risk factors for CVDs across different cultures.
They compared 15000 people who had a heart attack with a similar number of people who had not.
What was Yusuf et al. (2004) results?
They found chronic stressors with a strong link to hear attacks, included workplace stress and stressful life events.
The contribution of stress was greater than obesity and only third to smoking and high cholesterol.
Stress not only contributes to the development of CVDs in the first place but also makes existing disorders worse.
What is a limitation of research into stress and immunosuppression?
Some research shows that stress response can make illness less likely.
Dharbhar (2008) subjected rats to mild acute stressors and found that lymphocytes flooded into the bloodstream and body tissues in preparation for physical damage.
This shows that acute stressors may not have the same immuosuppressive effects as chronic stressors.
This shows the relationship between stress and the immune system is not yet fully understood.
What is a strength of research into the effect of stress on immunosuppression?
There is real-world application.
Dharbhar’s research into acute stressors could eventually lead to patients being given low doses of stress hormones before surgery.
This would stimulate their immune systems and improve their chances of making a full an fast recovery afterwards.
What is a limitation of research into cardiovascular disorders and stress?
The effects of stress on CVDs are mostly indirect.
Orth-Gomer et al. (2000) found that marital stress tripled the risk of a heart attack in women who already had CVD.
This is a different situation from demonstrating that stress causes CVDs to develop in the first place.
This suggests that stress increases a person’s vulnerability to developing CVDs mainly through indirect effects.
What is a strength of the link between CVDs and stress?
Song et al. (2019) identified more than 130000 people with stress-related disorders.
Other participants were unaffected siblings of these people and a million people with no stress-related disorders.
Compared with controls, people with stress-related disorders had a 64% greater risk of a CVD in the first year after diagnosis.
What are sources of stress?
Any feature of the environment that causes stress, including factors associated with work, everyday minor hassles and major changes in our lives.
What are life changes?
Significant and relatively infrequent events in people’s lives that cause stress.
They are stressful because we have to expend psychological energy coping with changed circumstances.
Who created the Social Readjustment Rating Scale (SRRS)?
Holmes and Rahe (1967)
What is the SSRS?
It measures stress by assigning a certain number of life change units to each item on a list.
What did Rahe (1972) find?
People scoring less than 150 LCUs in a given year were less likely to experience illness.
80% of those with a score over 300 LCUs experienced illness within the following year.
