Biological Psychology

Acute stress:

The ANS - immediate (acute) stressors activate the sympathetic branch of the ANS. The sympathetic nervous system (SNS) prepares the body for fight or flight, this is acheived by the release of noradrenaline, which activates internal body organs associated with fight or flight

SNS - Increased heart rate and blood pressure and increased pupil size

The Adrenal medulla - a second part of this response involves the adrenal glands, especially the adrenal medulla. neurons of the sns travel to the medulla causing it to release adrenaline inot the bloodstream

Chronic stress:

Preception of stressor by higher brain centers

   hypothalamus 

CRF      Pituitary gland

ACTH     Adrenal cortex

CORT                           

cortisol causes stress effects in the body

Consequences of the stress response - Cardiovascular problems theses stress responses are repeatedly activated, the heart and blood vessels begin to suffer from abnormal wear and tear. Immunosupression - too much cortisol supresses the immune system, shutting down the process that fights infection.

Acute stressors: Examination stress (keicolt-glaser et al. 1984)

HOW? natural experiment with students. asses the immune system functioning one month before an exam during the exam period itself.

SHOWED? immune system activity was significantly reduced from a blood smaple taken . this suggest that short-term stressors reduce immune system functioning.

VALIDITY? students may not constitute a representitive group.

Chronic stressors: relationship (Kiecolt-G)

How? Lab experiment with married couples, looking at the effects of unhappy relationships

Showed? wounds on their arms took longer to heal as a result of hostile behaviour

Validity? lacks ecological validty as it is a lab experiment

Evaluation of the stress-immune system relationship

1.) Health is affected by many different factors (genetics and lifestyle) therefore there is little variance left to be accounted for by stress

2.) health tends to be fairly stable and slow to change, therefore its difficult to demonstrate that exposure to particular stressors have caused a change in health

Individual differences

Women show more adverse immunological changes in the way they react to chonic stressors such as maritial conflict (keicolt - G)

As people age, stress has a greater effect on immune system functioning making it harder for the body to regulate itself (segerstrom and miller)