Stress as a Bodily Response.
Stress, The Three definitions.
- Response: a reaction to something in the environment
- Stressor: Any stimulus or situation imposing demands on an individual.
- Transactional model: An imbalance between perceived demands on an individual and their perceived ability to cope.
So, there we have the definitions. Next, we Have SEYLE (1956).
General Adaptation Syndrome, or G.A.S:
This model of stress is one which Seyle himself designed. It shows the body's response to stress. There are three stages. ALARM RESISTANCE and EXHAUSTION.
ALARM: A Stressor is perceived. HPA and SAM pathways are activated at the SAME TIME.
SAM - (Sympatho-adrenomedullary axis.)
- The Hypothalamus activates the sympathetic branch of the ANS.
- This Stimulates the Adrenal Medulla to secrete increased levels of adrenalin and noradrenalin (Stress hormones) and lead to the Fight or Flight response.
HPA - (Hypothalamic-pituitary-adrenal axis)
- The Hypothalamus stimulates the pituitary glad. Which releases ACTH.
- ACT travels to the adrenal cortex and releases cortisteroids which make fats available for energy, increase blood flow and stimulate behavioural responses, leading to the Fight or Flight Response.
RESISTANCE: If the stressor persists the body's response systems maintain their activation, with levels of stress related hormones and bodily arousal levels.
EXHAUSTION STAGE: Long periods of stress eventually exhaust the body's defense systems and its ability to maintain high levels of circulating stress hormones. Stress related illness may develop.
Now, he have the fun bit. The bits where psychologists tell each other they're wrong! :D
Evaluation of G.A.S
- Seyles work has been extremely influential in developing the whole area of research into stress. He pointed out the central roles of the HPA axis and the SAM pathway and the links between medicine and stress.
- It completely ignores Individual differences and how they perceive a stressor.
- Seyles work was animal based. (Rats)
Stress and Illness.
Welcome to the second area that we're covering :D Let's get to it.
Evidence suggests a relationship between prolonged exposure to stressors and the risk of cardiovascular disorders (any disorder of the heart and ciculatory system) Examples being:
- Hypertension (High Blood Pressure)
- CHD (coronary heart disease)
- Stroke (disruption of blood supply to the brain.
Basically, there is evidence that supports the fact that when your body has been in stage 3 for a long period of time, you develop these diseases. This long period of stage 3 can only be caused by a stressor if it continually stresses.