The Physiology of Stress (AQA A Level Psychology): Flashcards
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Define the General Adaptation Syndrome (GAS).
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Define the General Adaptation Syndrome (GAS).
The GAS is Selye's (1956) model explaining how the body responds to prolonged stress. It adapts and protects itself in the short term, but chronic stress leads to serious damage and stress-related illness.
What happens in the alarm reaction stage of GAS?
The body's initial 'shock' response. Resistance is briefly lowered, the fight-or-flight response is triggered (adrenaline release, raised heart rate) and resources are mobilised.
What happens in the resistance stage of GAS?
The body tries to cope with the stressor. Physiological activity stays high, using lots of energy, until stress hormones deplete. The parasympathetic nervous system is activated to conserve energy.
In the exhaustion stage of GAS, the body's resources become and the immune system weakens.
In the exhaustion stage of GAS, the body's resources become drained and the immune system weakens, and the person may relapse into alarm symptoms.
What did Selye call illnesses arising in the exhaustion stage of GAS?
Diseases of adaptation, such as raised blood pressure, coronary heart disease and depression.
What two structures make up the sympathomedullary pathway (SMP)?
The sympathetic nervous system and the adrenal medulla.
What does sympathetic arousal stimulate the adrenal medulla to release?
Adrenaline and noradrenaline into the bloodstream.
What effects do adrenaline and noradrenaline have on the body?
The heart beats faster, muscles tense, and the liver converts stored glycogen into glucose to provide energy for the fight or flight response.
True or False?
The SMP is the system that responds to chronic, long-term stressors.
False.
The SMP responds to acute, short-term stressors. The HPA system responds to long-term or chronic stress.
Once a stressor passes, the parasympathetic system reduces arousal in what is called the response.
Once a stressor passes, the parasympathetic system reduces arousal in what is called the 'rest and digest' response, prioritising energy conservation.
Describe the sequence of the HPA system.
The hypothalamus releases CRF, which causes the anterior pituitary to release ACTH, which causes the adrenal cortex to release cortisol.
How does cortisol help the body cope with a stressor?
By mobilising and restoring energy supplies. However, it also suppresses the immune system, which is damaging if stress is not resolved.
How is the HPA system self-regulating?
Through a negative feedback loop. High cortisol levels detected at the pituitary and hypothalamus trigger a reduction in CRF and ACTH, so cortisol falls.
How does prolonged cortisol damage the immune system?
In the chronic stage, such as stage 3 of GAS, raised cortisol reduces the production of antibodies to fight infection. Prolonged stress is also linked to heart disease and strokes.
What did Kiecolt-Glaser et al. (1984) find?
Students had lower levels of natural killer cells in blood taken during exams than in a sample taken a month before.
What did Timio et al. (1988) find?
Nuns' blood pressure was unchanged over time while working women's rose, suggesting long-term stress has a physical effect on health.
True or False?
Taylor et al. (2000) argued that fight or flight describes the female stress response well.
False.
They argued a more adaptive female response is 'tend and befriend': tending offspring and befriending other females for social support.
Why is GAS considered an important theory?
It was the first theory to explain the physiological effects of stress, influencing later theories and research into stress and health.
What practical benefit has research into the physiological stress response had?
It has contributed to the development of medicines to reduce the physiological stress response.
How does Lazarus (1999) challenge physiological accounts of stress?
People make cognitive appraisals: primary (is it a threat?) and secondary (do I have the resources to cope?), which physiological accounts ignore.
What did Speisman et al. (1964) find?
Heart rate changes to a film of a medical procedure depended on the soundtrack, rising if framed as traumatic and falling if framed as voluntary, so humans are not passive.
How did Mason (1971) challenge Selye's theory?
Monkeys' cortisol varied by stressor (cold increased it, heat reduced it, exercise had no effect), so stressors produce specific responses, not one non-specific response.
Early stress research used mainly male animals and participants, an example of bias.
Early stress research used mainly male animals and participants, an example of beta bias, so gender differences were overlooked.
True or False?
Physiological explanations of stress are holistic.
False.
They are reductionist, simplifying stress to bodily systems and ignoring how appraisal and coping strategies influence responses.
What does the immune system consist of?
Mainly white blood cells (leucocytes) travelling through the bloodstream, defending against antigens such as bacteria, viruses and cancerous cells.
Many leucocytes secrete , which bind to antigens and destroy them.
Many leucocytes secrete antibodies, which bind to antigens and destroy them.
Define immunosuppression.
Immunosuppression is the suppression of the immune system by the hormone cortisol, produced through HPA activation under chronic stress, which suppresses the production of lymphocytes.
True or False?
The cortisol involved in immunosuppression is produced in the adrenal medulla.
False.
It is produced in the adrenal cortex. The adrenal medulla releases adrenaline and noradrenaline.
True or False?
Stress directly causes infections.
False.
Continuous cortisol interferes with leucocyte activity and antibody production, so the immune system is less able to fight antigens and infection becomes more likely, e.g. colds at exam time.
How can the fight-or-flight response damage the arteries?
The elevated heart rate causes faster blood flow, which combined with blood thickening may damage artery walls or block arteries, impairing heart function.
How may stress cause cardiovascular disorders indirectly?
Through the stressed person's coping mechanisms, such as smoking or drinking alcohol.
What did Kiecolt-Glaser et al. (1995) find?
Small wounds healed more slowly in women caring for relatives with Alzheimer's disease, suggesting chronic stress reduces immune functioning.
What did Melamed et al. (2006) find?
Prolonged work-related stress was linked to cardiovascular disorders directly through inflammation and blood clotting and indirectly through poor health behaviours.
Why is data on stress and illness considered reliable?
Physical changes such as stress hormone levels, leucocyte numbers, heart rate and blood pressure are measured objectively.
Why can cause and effect not be established between stress and illness?
Other factors such as unhealthy lifestyle, smoking and drinking may also contribute to immunosuppression and cardiovascular disorders.
Why is it impossible to identify which stressors matter most for illness?
Particular stressors cannot be manipulated experimentally to test their effect.
Explaining illness through the HPA axis and cortisol is , ignoring social, psychological and lifestyle factors.
Explaining illness through the HPA axis and cortisol is reductionist, ignoring social, psychological and lifestyle factors such as sleep, diet and smoking.
Why is research into stress and illness described as nomothetic?
It aims to establish universal biological laws about how stress affects the immune and cardiovascular systems, but may overlook individual differences in coping and resilience.
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