The Bodily Response
The Hypothalamus is the part of the brain that responds to stress.
When the is a 'Stressor' in the enviroment, signals are sent to the hypothalumus. This triggers two processes within the body.
1. Sympathomedullary Pathway:
This is where the Hypothalamus triggers activity in the sympathetic branch of the autonomic nervous system. (which is a branch of the peropheral nervous system.) This branch becomes more in use when the body is stressed and is using energy.
These affects the body in a few ways, including:
- High blood pressure and heart rate
- Digestion slows down or even stops
- Muscles become more tense
- Breeating rate increases.
2. Pituitary-adrenal system:
This system produces a counter shock response which supplies the body with more fuel when the Sympathomedullary response starts to use up the body's resources.
i) The hypothalamus releases CRH (corticotropin-releasing hormone)
ii) Anterior pituitary gland releases ACTH
iii)ACTH stimulates the adrenal cortex
iiii) Corticosteroids are released into the blood stream to convert fat and protein into energy.
Stress and Physical Illness
Selye - General adaptation syndrome (G.A.S)
1.) Alarm stage: Our body's first reaction it to increase arousal levels so we are ready to make the necessary physical response. Also knows as the 'Fight or Flight' response
2.) Resistance stage: If stressor remains for a long time, our bodies adapt to the situation and we seem to be able to cope. However physically arousal levels would still be higher than normal.
3.) Exhaustion stage: after long term exposure we are unable to cope with the situation. Alarm signs may return and we may develop illnesses e.g. Ulcers, high blood pressure, depression etc.