User:Lynettefan2626/Psychology Unit 2 Revision

Stress is a Response to Stimuli in the Environment
Stress can mean one of two things:
 * 1. It can be the environmental stimulus that triggers a stress response.
 * 2. It can be the response to the stimulus.

Psychologists define stress as "the response that occurs when we think we can't cope with the pressures in our environment". This is shown in the below diagram.

Pressures/demands from the environment --> Judgement - do we believe we can cope? --> Yes - we deal with the demand (little/no stress) or No - fail to adequately deal with the demand (feel stress)

Sympathomedullary Pathway Stages (Short Term)

 * 1. Initial shock - Hypothalamus triggers Sympathetic Branch of the Autonomic Nervous System.
 * 2. This stimulates the Adrenal Medulla in the Adrenal Glands.
 * 3. This releases Adrenaline and Nor-adrenaline.
 * 4. Blood pressure rises, digestion increases, muscles tense, perspiration increases, and breathing rate increases.
 * 5. Prepares us for "fight/flight" situation.

Pituitary-Adrenal System Stages (Long Term)

 * 1. Hypothalamus triggers the release of CRH (corticotropin-releasing hormone).
 * 2. This stimulates the Anterior Pituitary Gland.
 * 3. This released the hormone ACTH (adrenocorticotropic hormone).
 * 4. This stimulates the Adrenal Cortex which is near the Kidneys.
 * 5. This then releases Corticosteroids which give us energy.

Changes in the Body Can be Seen as Having Survival Value
During evolution there were many threats to humans e.g. predators and other physical dangers. To successfully respond to them, we required a "fight or flight" response.
 * However, in modern society, stressors are more likely to be psychological than physical and are more long term.

Hans Selye - Three-Stage Response

 * 1. The Alarm Stage - Perceive stressor, react and increase arousal levels, ready to make necessary response "fight or flight".
 * 2. The Resistance Stage - If stressor remains for long time, body adapts to the situation and seems to be able to cope.
 * 3. The Exhaustion Stage - After long term exposure to a stressor, our bodies will eventually become unable to cope with the situation.

Long Term Stress Can Affect the Cardiovascular System
Krantz et al (1991) - stress and the heart
 * Method - 39 PPs did one of three stress-inducing tasks. Their blood pressure and the extent to which the vessels around their heart contract was measured.
 * Results - PPs with the greatest myocardial ischaemia showed the highest increases in blood pressure.
 * Conclusion - "Stress may have a direct influence on aspects of body functioning, making cardiovascular disorders more likely".
 * Evaluation - Test can be repeated, making results reliable. Problem with causation. Lacks ecological validity. Individual differences may play a part.

Stress Can Also Affect the Immune System
Brady et al (1958) - stress and the development of ulcers
 * Method - Monekys were put in pairs and given electric shocks every 20 seconds for 6 hour sessions. One monkey could push a button to postpone each shock. The other could not delay them.
 * Results - The one which could postpone the shocks were more likely to develop illness (ulcers) and later die.
 * Conclusion - "The illness and death was not due to the shocks, but due to the stress that they felt in trying to avoid them. In the long term, this stress reduced the immune system's ability to fight illness".
 * Evaluation - Test can be repeated, making results reliable. High ethical issues. Lacks ecological validity. Cannot generalise the results to humans.

The Same Immune System Suppression Happens in Humans
Kiecolt-Glaser et al (1995) - stress and wound healing
 * Method - A punch biopsy was used to create a small wound on the arms of 13 women who cared for relatives with Alzheimer's disease. A control group of 13 people also took part.
 * Results - Wound healing took an average of 9 days longer for the carers than those in the control group.
 * Conclusion - "Long term stress impairs the effectiveness of the immune system to heal wounds".
 * Evaluation - Doesn't account for individual differences or other factors. Small number of participants. Cannot be generalised to men.

Life Changes are a Source of Stress
Throughout our lives, we experience major life events e.g. death of a relative, marriage, moving house.

Holmes and Rahe (1967) Studies Whether the Stress of Life Changes was Linked to Illness'''

 * They assumed both positive and negative life events involve change, and that change leads to stress.
 * To test this assumption, they studies around 5000 hospital patients' records and noted any major life events that had occurred before the person became ill.
 * They found that patients were likely to have experienced life changes prior to becoming ill and that more serious life changes seemed to be linked to stress and illness.

They Ranked Life Events on the Social Readjustment Rating Scale

 * They made a list of 43 common life events and asked lots of people to give each one a score to say how stressful it was. They called the number that made up each score the Life Change Units.
 * Then they ranked the events from most to least stressful and called it the Social Readjustment Rating Scale.
 * They found a positive correlation between the likelihood of illness and the score on the SRRS.