Body's response to stress

There are two general ways in which the body responds to stressors: SYMPATHOMEDULLARY PATHWAY ( deals with acute stressors) an PITUITARY-ADRENAL SYSTEM (deals with chronic stress)
Sympathomedullary pathway
1. The sympathetic mervous system (SNS) and the sympatheic adrenal medullary (SAM) up up this.
2. Acute stressors activate the autonomic nervous system(ANS) which has 2 divisions.
  1. 1. The SYMPATHETIC NERVOUS SYSTEM (SNS)
    1. 'trouble shooter', It is highly responsive to stimuli and through activation is responsible for emotional states and heightened arousal.
  2. 2. The PARASYMPATHEIC NERVOUS SYSTEM
    1. 'house keeper'. It is responsible for maintaining equilibrium and calming bodily responses.
  3. These 2 divisions are opposing forces, interacting to produce bodily state at any given time.
    1. When exposed to an acute stressor, the SNS is activated and, simultaneously, the SAM system stimulates the release of ADRENALINE into the bloodstream from adrendal glands in the adrenal medulla.
      1. This hormone then prepares for fight or flight repsonse by boosting the supply of oxygen and glucose to the brain and muscles and suppressing non-emergency processes like digestion.
3. research to support this
  1. Taylor (2000) found that cute stress produces the fight-or-flight response in men, but the 'tend or befriend' response in women. This is because women produce more OXYTOCIN, a chemical promoting relaxation and nuturing, suggesting a gender difference in the activation of the sympathomedullary pathway.
4. Evaluation
  1. A gender difference in the activation of this may occur due to womens evolutionary role in caring for offspring. If women fought or fled when faced with danger, offspring would be placed in danger, reducing reproductive success. A better policy is to bond with other group members, most probably females.
  2. Much research into the Sympathomedullary pathway involves animals and thus presents a problem of extrapolation, as the stress-related behaviour of animals may not reflect the behaviour of humans. Humans are more likely to have a cognitive element to their stress response.
Pituitary-adrenal system
1. Prolonged, chronic stress activates the pituitary-adrenal system. This system is harder to initiate than the sympathomedllary system, being activate by stressors continuous over a period of time. These stressors alert the hypothalamus within the brain to stimulate the release of the chemical messenger CORTICOTROPHIN-RELEASING hormone into bloodstream.
  1. This then turn stimulates the pituitary gland to release ADRENOCORTICOTROPIC hormone (ACTH) which travels in the bloodstream to the adrenal glands just above the kidneys, triggering the relase of stress related hormones including (coritsol)
    1. The production of cortisol permits a steady supply of blood sugar, which provides an individual with a constant source of energy, allowing the body to deal with the stressor.
      1. Cortisol also releases the capability to tolerate more pain than usual, but also leads to impaired cognitive ability and reduced immune system performance.
2. Research into this
  1. Watson et al (2004) compared the pituitary-adrenal system functioning of 26 people with bipolar disorder, 27 people with bipolar disorder in remission and 28 healthy controls. They found heightened cortisol levels in bipolar sufferers, including those currently in remission, This suggests that pituitary-adrenal system dysfunction may be involved in the diisease process underlying bipolar disorder.
3. Evaluation
  1. There are individual differences with response levels. Mason (1975) found that different individuals produce different levels of stress hormones when exposed to the same stressors.
  2. People respond in more active ways to stressors involving cognitive and emotional factors. Symington et al (1955) found that conscious terminal cancer patients experienced more stress than those in a coma, as they indulged in a more stressful appraisal of their condition.
  3. The biological explanation of stress allows accurate, objective measures to be made.

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Body's response to stress

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	Created by courteneywaldron almost 11 years ago