3.7 - Stress (set A - physiology Of Stress And Stress Of Illness)

Question 1

What is stress?

Answer 1

A physiological bodily response to a stressor (anything in the environment that puts your body under pressure) disturbs the functioning of the body

• starts due to a mismatch between the demands made upon an individual and their ability to meet these demands (for example finding out you have a random test the next day)

Question 2

Explain the benefits of stress in the short term?

Answer 2

• helps improve quick cognitive functioning - eg making quick split decisions
• can be beneficial rather than negative by increasing performance

Question 3

Explain the sympathomedullary (SAM) pathway - what does it do?

Answer 3

ANS is part of the peripheral nervous system that acts as a control system,
maintaining homeostasis in the body - quick response to stress.

• deals with short term effects of stress

Question 4

Explain the role of cortisol regarding stress - how is it released/monitored? what does it target?

Answer 4

• adrenal gland picks up on signals from hypothalamus and pituitary gland which check cortisol levels within the blood and adjusts the levels accordingly by releasing more if necessary
• cortisol receptors receive and use the hormone differently - when the body is in fight or flight cortisol can alter or shut down functions (digestion/reproductive systems/growth processes or your immune system)

Question 5

Explain the function of cortisol?

Answer 5

• constricts blood vessels - increases blood pressure to enhance delivery of oxygenated blood (advantageous for short term fight-flight situations) but for chronic stress can cause vessel damage leading to CHD (coronary heat disease)
• regulates body’s stress response - controls use of fats/proteins and carbohydrates (metabolism)
• maintains blood pressure and immune function

Question 6

Explain the general adaption syndrome (GAS) - how was it developed?

Answer 6

• based on the work from Selye using rats - which would become ill and developed stomach ulcers, shrinking thymus and enlarged adrenal glands (even when given harmless injections)
• concluded the stress of the injections causes changes and that humans react the same way (called it a non-specific response - 3 stages)

Question 7

Outline and briefly explain the 3 stages of Selye’s general adaption syndrome (GAS)?

Answer 7

1) initial alarm reaction stage - occurs shortly after the stressful event

2) followed by resistance stage - bodies autonomic nervous system resists the impacts of the stressful stimulus

3) if stress continues, the exhaustion stage follows (body fails to cope with distressing stimulus)

Question 8

Explain in depth what happens in the alarm stage of Selye’s general adaption syndrome (GAS)?

Answer 8

• describes the body’s immediate reaction upon facing a threatening situation or emergency
• you are alerted to a stressor and your body alarms you with a range of physiological reactions that provide you with the energy to manage the situation
• hypothalamus triggers production of adrenaline/noradrenaline from adrenal glands

Question 9

Explain in depth what happens in the resistance stage of Selye’s general adaption syndrome (GAS)?

Answer 9

• If exposure to a stressor is prolonged, the organism enters this stage
• During this stage, the initial shock of the alarm reaction has worn off and the body has
  adapted to the stressor (heart rate reduces, muscles relax)
• body remains alert and ready to respond - lower intensity compared to alarm reaction

Question 10

Explain in depth what happens in the exhuasation stage of Selye’s general adaption syndrome (GAS)?

Answer 10

• If exposure to a stressor continues over a longer period of time
• no longer able to adapt to the stressor- body’s ability to resist becomes depleted as physical wear takes its toll on the body’s tissues and organs (raised heart rate, ulcers and cardiovascular problems)
• Illness, disease and other permanent damage to the body

Question 11

Explain how the sympathomedullary (SAM) pathway works?

Answer 11

Hypothalamus activates sympathetic branch of ANS - causing adrenal medulla to release adrenaline and noradrenaline from

• prepares bod for for fight-flight (increased heart rate, breathing and inhibited digestion)

Question 12

Explain the hypothalamic-pituitary-adrenal (HPA) axis?

Answer 12

In response to stressful situation - hypothalamus activates the pituitary gland, which causes ACTH to be released

• ACTH stimulates the adrenal cortex to release cortisol
• These stress hormones have a number of functions - cause the liver to increase release of glucose and suppress the immune system

Question 13

Explain Selye’s method which led to discovery regarding the fight or flight response?

Answer 13

• was conducting experiments relating to hormone production using rats - noticed similar side effects regardless of life-threatening stimulus (organs experienced changes to shape, colour and developed ulcers ext)
• observed physiological responses to these stressful situations
• termed this collection of responses general adaption syndrome (GAS)

Question 14

Explain the effect of stress on the immune system - mention immunosuppression?

Answer 14

Can have negative impacts on the immune system

• sustained production of cortisol interferes with white blood cells (leukocytes), reducing their ability to fight infection - known as immunosuppression
• long term stress causes shrinkage and damage to thymus gland - permanently reduces number of T-cells (WBCs) available to fight antigens (increasing vulnerability to illness)

Question 15

Explain the different cells involved in immune response?

Answer 15

Cellular immunity includes number of different cells T-cells (produced in thymus gland) and B cells (produced in bone marrow)

• work together to protect body

Question 16

Explain research support into the impacts of stress on the immune system - focus on cohen 1993?

Answer 16

Gathered 394 participants and had them complete questionnaires on stress and stressful events experienced in their life - calculated a stress

• infected participants with common cold - 7 days later the number of participants who developed a common cold was recorded

**concluded - life stress and negative emotion (depression) reduced immune system effectiveness

Question 17

Evaluate research support into the impacts of stress on the immune system - focus on cohen 1993?

Answer 17

• indirect study - no direct measure of immune function - supported by other research who also found correlation between developing cold and negative events (positive)
• did measure health outcomes - showing a relationship between life stress and illness (positive)
• no direct manipulation of IV (stress index) - so no cause and effect relationship can be established (negative)
• study does not tell us which element of the stress index is important (negative)

Question 18

Explain research support into the impacts of stress on the immune system - focus on Glaser 1984?

Question 19

evaluate research support into the impacts of stress on the immune system - focus on Glaser 1984?

Question 20

Explain how cardiovascular damage can occur through stress - mention acute and chronic stress?

Answer 20

Acute stress (short term) has minimal impact on cardiovascular system

Fight or flight increases blood pressure and heart rate - chronic stress can lead to damage to blood vessels (role of cortisol) as they are constricted and pumped at high pressure leading to arterial damage over time

• arteries can become scarred, hardened and less elastic (reduces ability to provided sufficient blood)

Question 21

Explain the illnesses and health concerns caused by acute and chronic stress?

Answer 21

• high blood pressure (HBP)
• Coronary heart disease (CHD)
• stroke

all of these linked with other factors - only correlational evidence - can not say chronic stress is 100% linked with these problems - other variables involved (poor diet, smoking, lack of exercise)

Question 22

Evaluate research and ideas regarding stress and its impacts of the cardiovascular system and immune system?

Answer 22

• stress increases risk of immunosuppression and cardiovascular disease - no cause and effect, only correlational evidence
• the effect can be mediated (helped) by a number of different things - eg personality type, smoking and diet - therefore can not be conclusive that stress causes heart problem
• pre-existing CHD will be made worse by stress
• research by Dharbar found in rats that mild stressors had a positive impact on the immune system - body was prepared for physical damage (suggests acute stress does not always have a negative impact on immune system as opposed to chronic stress)