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Flashcards in Stress - Biological Explanation Deck (29):
1

What are the Two Biological Explanations of Stress?

1. Adrenaline + Acute Stress
2. Cortisol + Chronic Stress

2

What is the SAM System?

- Sympathomedullary Pathway
- Involves sympathetic nervous + adrenal medulla
- SAM = Sympathetic-Adrenaline-Medulla

3

Describe the SAM System

Stressor
|
Hypothalamus
|
Sympathetic Nervous
System stimulated
|
Adrenal Medulla
(Central part of adrenal gland)
|
Adrenaline + Neurodenaline
Released
|
Triggers Flight or Fight Response

4

What are the Physical Responses to the Body going into Flight or Fight?

- Heart rate increases
- Blood pressure increases
- Fats + carbohydrates mobilised
- Activity in digestive tract slows
- Increase in respiration rate
- Dilation of pupils
- Inhibition of digestion
- Movement of blood away from skin

5

Where is the Adrenal Gland Located?

- Just above kidneys

6

Why is SAM System Known as the Fight or Flight Response?

- Changes caused by the Release of adrenaline + noradrenaline

7

What are the Physiological Responses to Acute Stress.

- Body diverts blood away from inessential areas to more important areas (e.g. muscles)
- Oxygen is carried to the muscles to allow them to work harder + release energy
- Salivary glands are constricted causing mouth to go dry
- Body produces sweat to cool down an overworked system - allows body to react offensively/defensively

8

Explain the Differences in the Stressors from 1000s of Years ago to Today’s Stressors

- Same Stress response but the stressors are not the same
- Flight/Fight Response is triggered - Today’s Stressors don’t typically require energy, individual is left in a permanent state of arousal which causes problems for the body

9

How are High Levels Adrenaline + Noradrenaline are Linked to Cardiovascular Disorders?

- Body’s Stress response increases heart rate, pumping blood around the body at a higher pressure + faster speeds - increased mechanical structure can simply ware away at the blood vesicles lining

10

Describe the Process of Atherosclerosis

- Involves scaring of vessels acting as a collection point for fatty acid + glucose that’s circulating the body
- Leads to the formation of clumps that slowly block the vessels which can lead to a heart attack

11

What did Heidt’s 2014 Study Show?

- Mice + Stressed medical staff
- Cases where individuals had thickening activitie, the added stress led to an increases in umber of white blood cells which cause inflammation + produces lesions
- Blood platelets + clotting proteins rush to fill wounds - increases Risk of heart attack

12

Adrenaline + Acute Stress Evaluation
Supporting Evidence

- POSITIVE

- Leor (1996) = increase deaths caused by cardiovascular problems on day of Northridge earthquake in 1994
- Using earthquake offers a unique opportunity to asses the effect of an Acute stressor without having to trigger one in a lab (unethical + unrealistic)
- Leor’s research supports link between Stress,adrenaline+heart problems

- Cardiomyopathy (broken heart syndrome) affects people who suffer severe emotional stress after an event such as spouse’s death - often misdiagnosed asa heart attack but involves a massive release of adrenaline which paralysis the bottom of the heart - can cause death but most patients fully recover - supports link between Acute Stress + heart problems

13

Adrenaline + Acute Stress Evaluation
Causal Factor

- NEGATIVE
- Dimsdale (2008) = Stress not only cause of heart disease- other factors such as smoking + high cholesterol
- Liu (2015) = UK Million Woman Study suggests that pervious research fails to address issues of cause + effect
- Liu also found that people who are ill report higher stress levels/lower happiness levels rather than reverse
- 700000 women filled in a questionnaire about happiness/everyday life + health - 10 year follow up 4% dead - after controlling several factors (e.g. lifestyle+demographic) - death rates amongst unhappy people were no greater than happy people

14

Adrenaline + Acute Stress Evaluation
Challenge Vs. Threat

- A point to consider
- Blascovich+Tomaka (1996) = suggest body responds differently to stressful situations dependent on whether we see it to be a challenge or a threat
- If we see it as a Challenge our blood vessels relax, heart beats more powerfully + performance is likely to improve
- If we see it as a Threat then heart beats faster + it has a negative impact on heart

15

Adrenaline + Acute Stress Evaluation
Gender Differences

- NEGATIVE
- Fight/Flight response tends to focus on males - women respond differently
- Taylor (2000) = females’ Stress response is ‘tend + befriend’ in environmental evolutionary (EEA)
- Women have been adapted to deal with stress by nurturing their young (tend) + creating social networks (befriend)- if they fled/fought an attacker they’d be putting offspring at risk
- ‘Tend+Befriend’ may bd caused by a release of Oxytocin - makes individuals more relaxed + reduces fear response - can be released in both males+females - males produced increased levels of testosterone when stressed which reduces effects of oxytocin

16

How is the Role of Dopamine Applied to modify addiction? (Using Varenicline)

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17

What System Releases Cortisol?

- Hypothalamic Pituitary Gland - Slower Response

18

Describe the Hypothalamic Pituitary Gland?

Perception of Stressor
|
Hypothalamus
| produces
Corticotropin Releasing Hormone (CRH)
| causes
Pituitary Gland
| releases
Adreno Corticotropic Hormone (ACTH)
|
Stimulation of Arenal Cortex
|
Release of Cortisol

19

What are the Physiological Effect of the Release of Cortisol?

- Liver releases store glucose
- Decreased activity of immune system

20

What is Cortisol?

- Belongs to the glucocoticoids family

21

What is Cortisol's Function?

- Usual function is to play a role in central nervous system - involved in learning /memory/regulating glucose for energy + the immune system

22

What Happens When Cortisol is Released?

- Lowers sensitivity to pain + releases glucose for energy over a sustained period of time which allows the person to deal with the stressor better
- Effects cognitive performance (especially memory) + may lower immune response

23

What Effect does Cortisol Have on Memory?

- Impairs memory
- Kulmann (2005) = Administer cortisol to 30 women + made them learn 30 words - those given cortisol showed significant reduced ability to recall words, particularly negative words - possible effect on memory has implications for performance under stress (mind goes blank)

24

What are Cortisol's Effects on Health?

1. Immunosuppression
- Faced with stressor, the immune system is seen as non-essential - shuts down to divert energy else where
- Cortisol does this by reducing inflammation caused by the immune response - if stressor continues then goes into immunosuppression - put at increased risk of illness
- Illustration by people with Cushings Syndrome - have high levels of cortisol + at high risk of infectious diseases

2. Kiecolt-Glaser (1984) = Effects of stress on immune system by measuring by natural killer (NK) cell activity in 75 medical students 1 month before exams + during exams - NK cells activity significantly reduced in blood sample taken during exams - students also completed SRRS to assess stressful life events - Highest Score = lowest NK cell activity

25

Cortisol + Chronic Stress Evaluation
Low Levels of Cortisol Also Causes Health Problems

- NEGATIVE
- Research shown that it is not just high levels that can cause health problems - for many it is not until stressor is removed that they get ill
- Helm (2000) = low levels of cortisol link to health condidtions such as chronic fatigue + PTSD
- Exact mechanisms are unclear but what may be more important is to have a balance of cortisol levels over time

26

Cortisol + Chronic Stress Evaluation
Issues in Research Studies

- NEGATIVE
- Difficult to establish the the cause + effect between stress-related cortisol + subsequent illness
- When people are stressed they often change eating/sleeping habits. They also might consume more alcohol/caffeine - raises cortisol levels
- Lopaz-Duran (2009) - variations of cortisol releases in children who were placed in stressful situations - peak times of cortisol release varied from 10-60 mins after stressor - boys showed a greater cortisol activation in responce to stressor

27

Cortisol + Chronic Stress Evaluation
Stress in Good for Immune System

- POSITIVE
- Stress may enhance the activity of the immune system
- Evans (1994) = looked at the activity of an antibody (SLGA) which protects against infection - the researchers arranged for students to give talks to other students (immediate stressor). Those students showed increased levels of SLGA - SLGA levels decreased during exam time
- Evans (1997) = proposed that stress may have 2 effects
1. up-regulation (increased efficiency) for short short term acute stress
2. Down- regulation (decreased efficiency) for long term stress

28

Cortisol + Chronic Stress Evaluation
Stress Doesn't Always Raise Cortisol Levels

- NEGATIVE
- Lewis (2007) = reviewed of studies demonstrate a variation in response to examinations stress ranges from 58% decline - 95% increase in cortisol levels - Lewis' own study he found no difference
- Variations in findings may be due to factors such as:
1. length of time
2. nature of threat
3. emotions associated with stressor
- lack of longitudinal studies demonstrate the fluctuations of cortisol levels over a long period of time

29

Cortisol + Chronic Stress Evaluation
Social Support

- A POINT TO CONSIDER
- Seltzer's study
- Sample of girls 7-12 put into a stressful situation
- Given chance to be comforted by their mothers - oxytocin was released
- Cortisol levels were reduced compared to a control group