1. Stress as a bodily response The body’s response to stress, including the pituitary-adrenal system and the sympathomedullary pathway in outline Stress-related illness and the immune system

2. Sympathomedullary pathway When somebody is affected by an acute stressor, the ‘fight or flight’ response is usually stimulated. The process 1. The ANS (autonomic nervous system) is aroused which is split into the SNS (Sympathetic Nervous System) and the parasympathetic branch. 2. When the SNS is aroused, noradrenaline is released into the bloodstream which increases heart rate, pupil size and blood pressure. 3. The SAM (sympathomedullary system) is aroused at the same time as the SNS and the SAM allows adrenaline to be released from the adrenal glands, the adrenaline increases amount of oxygen in the bloodstream going towards the muscles and the brain. 4. The SNS and SAM is used to prepare the animal for the ‘fight or flight’ response but the parasympathetic branch put the animal into a state of relaxation after this response has been carried out.

3. pituitary-adrenal system Higher centres of the brain send a message to the hypothalamus that there are chronic stressors and the hypothalamus sends the hormone, CRF, to the pituitary glands. The pituitary glands then send the hormone, ACTH, to the adrenal cortex. The adrenal cortex sends the hormone, cortisol, in the bloodstream to the rest of the body and the effects of cortisol are lower sensitivity to pain and immunosuppression. This cycle is repeated and the levels of ACTH and CRF can be altered to alter the level of cortisol in the body.

4. Exam Question 1 Outline the main features of the pituitary- adrenal system. (3 marks)

5. Answer Main features are that the hypothalamus communicates with the pituitary gland, causing it to release ACTH. This hormone is then detected in the bloodstream by the adrenal cortex, Which then releases corticosteroids. The corticosteroids have a range of effects, such as causing the liver to release glucose. An accurate diagram could also receive credit. 1 mark for a brief outline and 3 marks for a correct and coherent outline of the features. How did you do?

6. Stress-related illness and the immune system Kiecolt-Glaser et al (1984) did a natural experiment to investigate the effect of acute stress on illness levels. They used students as participants and measured their immune system activity a month before their examinations and measured it again during the examinations. They found that immune system activity decreased during the exams, presumably because there is more acute stress. Evans et al – showed how acute stress could boost immune system activity. They conducted an experiment which used students as participants; the students were given a small talk to give to other students which is a mild acute stressor. The amount of slgA (an antibody) during the time of the talk was higher than the amount of slgA before they had to give the talk.

7. Stress-related illness and the immune system Kiecolt-Glaser et al (2005) – showed how chronic stressors negatively affect immune system activity. They did a laboratory experiment which used hostile couples and less hostile couples as participants. All of the couples were given blister wounds and the time it took for the wounds to heal was a measure of how much the immune system activity was. It took longer for the more hostile couples to heal their blister wound than the less hostile couples. This shows that chronic stressors reduce immune system activity. Stress can also have an indirect effect on illness as it is associated with all manner of bad habits (coping strategies), for example smoking, drinking alcohol to excess, poor diet due to lack of time, lack of exercise for the same reason, lack of sleep etc.

8. Question Sandy and Vandita play for the same netball team. Two weeks ago, while playing in a competition, they both grazed their elbows. Vandita’s wound is healing well, but Sandy’s wound is taking much longer to heal. Sandy is very worried about the plans for her wedding and her forthcoming house move. Using your knowledge of psychology, explain why Sandy’s wound is taking longer to heal than Vandita’s. (4 marks)

9. Answer There are a variety of different ways to answer this question: credit appropriate alternative answers. Candidates could focus on critical life events as well as the underlying biological mechanisms. Research has shown that stress reduces the effectiveness of the immune system. People experiencing long-term stress are more likely to become ill and to take longer to heal than those who are not stressed. Sandy is experiencing two events that are on the SRRS and are known to be major stressors. 1 mark for a basic statement of the relationship between stress and the immune system and a further 3 marks for elaboration of this. For full marks, the elaboration must be linked to Sandy’s situation. Credit can also be given to research evidence used to support/illustrate the explanation.