The bodies reponse to ST stress
The Sympathetic Medullary System
The bodies response to acute stress. The hypothalamus activates the sympathetic branch of the autonmic nervous system which stimulates the adrenal medulla. Adrenaline and noradrenaline is then released into the bloodstream which causes a flight or fight response.
This creates physical effects on the body including:
· Heart rate and blood pressure increase in order to get blood quickly around the body. Digestion decreases in order to direct blood to the brain and muscles. Perspiration increases in order to cool body down and burn more energy. Breathing rate increases so more oxygen is sent to the muscles. Muscles become tense so the body is more responsive.
The bodies response to LT stress
The bodies reponse to long-term stress which helps the body adapt to the long-term effects it causes.
Hypothalamus triggers the realse of CRH which then stimulates the pituitary glands. These then release a hormone called ACTH which travels through the blood and stimulates the adrenal cortex where corticosteroids are released to convert fat and protein into energy.
What is stress and the role of the hypothalamus
Stress is an environmental stimulus that triggers a stress response.
The scientific explanation: The reponse which occurs when we think we cannot cope with the pressures in our environment.
The part of the brain which responds to stress when signals are recieved from the cerebal cortex. This triggers 2 processes - The pituitary-adrenal system and the Sympathemedullary pathway.
Stress related illness and the immune system
The immune system defends the body from foreign bodies antigens. Acute stress has a direct effect on immunity as ANS sends nerves directly to the tissues of the immune system. Long-term stress affects the immune system because too much cortisol supresses it's functioning.
Key study: Kiecolt-Glaser et al.
A natural experiment where blood was taken from 75 1st year medical students. (taken 1 month before exam period started and again during exams). T-cell activity was measured and they found more t-cells in the sample taken a month before. Natural experiment therefore variables including drugs and alcohol cannot be controlled.
Key study: Cohen et al.
394 ppts had their stress index measured using questionnaires and were then given a cold virus. A direct correlation was found between high levels of stress and the developement of the cold virus. Difficult to establish cause and effect relationship as health can be affected by many factors.
Daily hassels as a source of stress
A daily hassel is an irritating daily occurence such as losing your keys or missing the bus.
Key study: Kanner
Daily hassels scale created with possible 117 events. 100 adults completed the scale for 9 months while rating the hassels in terms of severity. It was found those with the higher scores on the hassels scale were more likely to have physical and psychologyical health problems. These results suggest hassels are linked to stress and health. Correlation so hard to establish cause and effect.
Key study: Gervais
Nurses kept a record of daily hassels and daily uplifts for a month when at work. Hassels increased job strain and decreased job performance however the uplifts counteracted this and improved performance. Problem with accuracy of recall as they are only minor events - however noting them when each happened would of improved this problem.
Flett: Hassels are more stressful than life events as there is less social support because everyone experiences daily hassels.
Life changes as a source of stress
A life change is an event which creates a significant adjusment to life such as experiencing a death within the family.
Holmes and Rahe created the Social Readjusment Rating Scale (SRRS) in order to test how life changes can affect stress related illness. It consisted of 43 life events after an analysis of over 5000 people.
Key study: Rahe
2500 american sailors were given the SRRS scale and asked to complete in terms of the previous 6 months. Over the following 6 months details of their health were recorded. A correlation of +0.118 was found which suggests stress increases the chance of illness however it is not the only factor. Sample only included american males therefore it is ethnocentric which reduces the validity of the study and findings.
Kanner: Criticised SRRS as life events are not everyday occurences and people are more affected by events which happen on a daily basis - this is why he developed the hassels scale.
SRRS doesn't account for individual differences - assumes all stressors are same for everyone.
Work-related stress is the harmful reaction people have due to pressures and demands placed on them at work. Lack of control in thr workplace is having little influence over the type or amount of work and where or how you complete it.
Key study - Marmot et al
Longitudinal study looking at the correlation between lack of control and illness. 10,000 civil service employees completed a questionnaire on workload, job control and social support. Signs of Cardiovascular disorder were also checked. 5 years on ppts were reassessed. NO link found between high workload and stress related illness although other studies such as Johansson et al found repetitive jobs with high levels of responsibility. Results also showed the civil service employees with more control over their workload and better social support had less cardiovascular problems. Self report could of meant concerns over job may have led to lies which reduces validity. Illness could be due to other factors such as diet.
(INDIVIDUAL DIFFERENCES) Lazarus' - Believes that the degree to which a workplace stressor is percieved as stressful depends on the persons ability to cope. Similarly Schaubroeck et al found some people are less stressed by having no control or responsibility and show better immune responses in such situations.
Personality factors and stress
Key study - Friedman and Rosenman
Investigated the link between Type A personality (Competitive, self-critical, impatient and hostile) and the development of heart disease. 3000 American men aged 39-59 were identified as type A or B personality then monitored for 8 and a half years where their lifestyle and health were assessed. 257 of the men developed heart disease where 70% were type A. A longitudinal study therefore it was a good indication of the long term effects of personality and stress related illness. Natural experiment so cause and effect cannot be clearly established.
Kobasa and Maddi - Claimed that having a 'Hardiness' personality was a protective factor and therefore individuals may be less likely to suffer from stress related conditions. Hardiness personalities consist of: Feeling in CONTROL of stressful situations; See stress as a CHALLENGE and opportunity for personal growth and COMMITMENT as they do not give up easily.
Key study - Kobasa
800 business executives completed SRRS scale and a hardiness test. 150 of the males were experiencing high levels of stress. A correlation was found between low levels of stress and scoring high on the three characteristics of the hardy personality. White male middle class sample so cannot generalise. Correlation was found but cannot establish cause and effect.