Psychology - Stress

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Psychology - Stress

  1. Analyse what stress is and the main sources of stress

Defining stress is not an easy thing to do. Psychologists take the same view as physicists, who see stress as a force or pressure that is exerted on the body,  except they look at stress in terms of the demands it makes on the organism and the efforts an organism has to make in order to adapt, cope or adjust to its demands.

When defining stress it’s important that the definition includes the interaction between external stressors and our physiological and psychological response to them. The definition must also acknowledge the role played by cognitive factors, because the way a person appraises a potential stressor affects the way they react. It is also important to acknowledge that stress can have positive as well as negative effects, since stress helps to keep us healthy and alert.

Lazarus & Folkman (1984) defined stress as ‘a pattern of negative physiological states and psychological responses occurring in situations where people perceive threats to their well-being which they may be unable to meet’.

Hans Selye, who was a Canadian researcher, was conducting experiments sixty years ago hoping to discover a new sex hormone. His experiments consisted of exposing mainly rats and some other animals to unpleasant or harmful stimuli such as injections, extreme cold and even vivisection.

Selye discovered that all of the animals showed a very similar series of reactions to the stressors, including an expansion of the adrenal cortex, a reduction in the size of the thymus gland and ulcers in the stomach and small intestine, and concluded that the body’s response to a stressor is non-specific.

Selye argued that when an organism is faced with a stressor, the body reacts and gets ready to defend itself. If the stressor is then adequately dealt with, the body will then return back to its normal state, but if the stressor persists and the body is continually exposed to the stressor and is unable to manage it, the organism could be damaged as a result by tissue damage, increased susceptibility to illness, and even possibly death.

Selye called this non-specific response that was the result of a stressor the General Adaption Syndrome (GAS), also known as the pituitary-adrenal stress syndrome.

Stage One: alarm. When the threat or stressor is identified or realised, the body’s stress response is a state of alarm, known as the ‘flight or fight’ or acute stress response. This response was first described in 1915 by Walter Cannon. His theory states that organisms react to threats with a general discharge of the sympathetic nervous system, which primes the animal to either fight or flee.

In the initial shock phase of the alarm reaction, the body’s blood pressure drops and the muscles tense. This is then replaced by the counter-shock phase, which is an alerting response to a possible threat or physical injury. The reactions in the body during the counter-shock phase are initiated by the hypothalamus and are regulated by the sympathetic branch of the autonomic nervous system and the endocrine system.

When the body perceives a stressor, the hypothalamus in the brain releases a corticotrophic releasing hormone. This hormone stimulates the pituitary gland to release adrenocorticotrophic hormone (ACTH), and the ACTH then makes the adrenal cortex of the adrenal gland enlarge and release corticosteroids which help the body to fight inflammation and allergic reactions.

The hypothalamus also activates the sympathetic branch of the autonomic nervous system, which make the adrenal medulla of the adrenal glands (situated just above the pancreas) enlarge and secrete adrenaline and noradrenaline, otherwise known as the stress hormones.

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The body then starts a frenzied cycle of physiological activity such as a faster heart rate and higher blood pressure to send blood to the parts of the body that will need it during. The liver releases glucose to be used as fuel for quick energy, and the persons breathing rate will increase to supply enough oxygen to the muscles. The muscles will tense to prepare for an adaptive response, such as sprinting away, and there is an increase in blood coaguability so the blood will clot quicker if the body gets injured. The body will perspire to ...

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