Psychology - Stress

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  • Created by: Natalie
  • Created on: 13-04-08 13:25

ANS

Autonomic Nervous System causes automatic response & regulates the body.

1. Parasympathetic branch: calming, slows you down, stimulates digestion & sexual activity, controls F/F response > Homeostasis (maintaining equilibrium).

2. Sympathetic branch: arousing, speeds you up & gets you ready (adrenaline), responsible for F/F response > Homeostasis (maintaining equilibrium).

>> Stress: a bodily response.

Stressor > Hypothalamus >Sympathetic Nervous System > Increased heart rate e.t.c > F/F repsonse.

Stressor > Hypothalamus > Sympathetic Nervous System> Adrenal Medulla > Stress hormones released into bloodstream > F/F response.

Stressor > Hypothalamus > CRF > Pituitary Gland > ACTH > Adrenal Cortex > Stress hormones released into bloodstream > F/F response.

(Hormones)
(Effects)

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Physiology Of The Stress Response

It arouses the body & prepares us for F/F response.

- Stressors set off a chain of events which activate various parts of the nervous & endocrine system.

- Stressor is detected by higher parts of Central Nervous System (CNS).
> Information is passed to Hypothalamus.

- This forms part of 2 systems which both generate the stress response.

The Hypothalamic-Pituitary-Adrenal-Axis.

Hypothalamus is connected directly to the pituitary gland via the infundibulum (or pituitary stalk).

Hypothalamus > CRF > passes through Infundibulum > pastposterior lobe and into anterior lobe > ACTH.

(Hormones)

- It produces the hormone corticotrophin-relasing factor (CRF) which stimulates the Anterior (front) section of the pituitary gland.

- Anterior pituitary released adrenocorticotrophin hormone (ACTH) into the bloodstream which travels to adrenal gland (located above the kidneys).

- Adrenal glands have 2 sections > Cortex & Medulla > each releases different hormones.

ACTH affects Adrenal Cortex causing it to release a further set of hormones > Corticosteroids > which allow metabolism ofcarbohydrates & fats.
> This provides energy for body.

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GAS

General Adaption Syndrome.

3 stages of response: ALARM / RESISTANCE / EXHAUSTION.

Alarm - effects on body:
> Adrenal Pituitary Cortex is activated.
> ACTH released.
> Adrenal System releases glucocorticoids.
>> More energy = ready for F/F response.

Affectsability to function properly by:
> Increased blood supply to brain & muscles.
> Decreased blood supply to skin, bowels & stomach.
> Mood change - serious.
> Reduced saliva.
> Increased blood pressure & respiration rate.
> Dry skin.
> Impotence & irregular periods.
> Adrenaline produced.
>> BECOME STRESSED!

Resistance - effects on body:
> Parasympathetic Nervous System 'calms down' resource overuse from alarm stage.
> Conserves resources.
> Increases concentration.
>> F/F response is LESS effective.

Affects ability to function properly by:
> Denial/overloading = coping strategies.
> Slower heart rate.
> Saliva stimulated.
> Bladder contracted.
> Constricted pupils & airways.
> Adrenaline levels reduced.
>> Hinders F/F response > COPE WORSE!

Exhaustion - effects on body:
> Physiological systems & resistance to stress - ineffective.
> Immune system shrinks.
> Impotence/menstrual disorders/tiredness/heartburn/ulcers/coughs/hypertension/migraines e.t.c.

Affects ability to function properly by:
> Making it harder to fight off illnesses.
> Prone to stress-related illness/diseases, e.g. depression.
> Unable to function > WE'RE KNACKERED!

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Selye (1936)

Selye observed rats showing physical changes which seemed to be related to the number of stressful procedures he subjected them to.

- Rats exposed to variety of non-lethal injections.
- Rats made to exercise & suffer injury/mutilation &/or poisoning.

Results:
> Long-term response to stress - exhaustion stage for the rats.
> The injections caused stress, just as the other factors did.
> Rats adrenal glands became enlarged; thymus shrunk & stomach developed ulcers.

ETHICAL ISSUES:

> Is it right to deliberately inflict pain & stress on animals?
> Could alternative methods have been used?

> Problems generalising: rat > human physiology have similarites & differences.
> Human stress is meditated by psychological factrs aswell as physical ones.

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