Stress 1

Question 1

What is different about the what causes stress in animals and humans?

Answer 1

Usually in humans it’s things like deadlines and traffic whereas for animals it’s predators and starvation

Question 2

What is a stressor?

Answer 2

A situation that causes stress to a system

Question 3

What is stress reactivity?

Answer 3

The way that we respond to a stressor - our tolerance for stress

Question 4

How does our body change when we feel stress?

Answer 4

• Changes in breathing
   Increased risk of asthma attack/emphysema
   Hyperventilation during stress – increased risk of panic attack
• Exacerbate existing mental health conditions
• Changes in eating behaviour
• Diarrhoea/ constipation

Question 5

What sort of problems can chronic stress cause?

Answer 5

• Muscles of body – constant state of guardedness
• Tension-type headache/ migraines
• Long-term heart/ blood problems
   Hypertension
   Heart attack

Question 6

What was Everson - Rose’s experiment on Chronic stress and atherosclerosis?

Answer 6

• Multi-ethnic study of atherosclerosis
• Population based study of 6749 adults aged 45-84 years, free of cardiovascular disease
• Followed up over average 8.5 years
• Stress measured as burden in 5 domains
   Health problems
   Health problems of others
   Job or ability to work problems
   Relationships
   Finances
• Chronic stress (i.e. burden) at baseline predicted increased likelihood of stroke over the follow-up period (10% increase)
   held after accounting for race, age, sex, education

Question 7

What do you get with the flight and fight response?

Answer 7

short term gain:
- arousal, increased blood supply and sugar and preparation for a violent burst of energy.
Long term negative consequences .

Question 8

What were the causes of mortality in 1900 compared to now?

Answer 8

Then it was acute illnesses such as pneumonia and childbirth. Now it is more from cumulative damage such as heart disease

Question 9

How does long-term stress affect our immune systems?

Answer 9

Stress via cortisol can directly suppress the activity of the immune system

Question 10

What was Keller’s 1983 experiment to do with stress and the immune system?

Answer 10

• Inescapable shock= reduced B and T cells
• Removal of adrenal gland
   No immune change to shock
   But normal immune response to antigen (bacterial protein)

Question 11

What was Kiecolt-Glaser et al. 1995 experiment into the immune response and stress?

Answer 11

• Bereavement, caring for other with Alzheimer’s disease, marital disease tends to reduce immune function
• 13 caregivers for relatives with dementia
• 13 controls
• Matched for ages, household income
• Gave them a punch bioscopy (small cut)
• Wounds took longer to heal in caregivers compared to controls suggesting immune system likely to be affected by immune system

Question 12

What was Glaser et al.,’s 1987 experiment on stress and the immune system?

Answer 12

• Blood samples from 40 1st year medical students
• During exam periods and 1 month before exams
• During exams, immune system responses weakened
• Heightened risk of contracting acute infections
• Increased risk of Epstein Barr virus

Question 13

What are the two stress response routes?

Answer 13

a slow response of hormones through the HPA axis, and a fast change in the activity of different organs through the autonomic nervous system

Question 14

What does the HPA axis consist of and what do they do?

Answer 14

1. The hypothalamus, located centrally in the brain, releases a hormone called corticotrophin releasing hormone (CHR) into the bloodstream
2. Receptors in a small gland between the hypothalamus, called the pituitary gland, detected the circulating CRH which causes the release of Adrenocorticotropic Releasing Hormone (ACTH) into the bloodstream
3. The adrenal gland, which is located on the top of your kidneys detect the circulating ACTG and release the hormone cortisol into the bloodstream. Cortisol plays several important roles in the bodies response to stress

Question 15

What does Cortisol do in response to stress?

Answer 15

• Cortisol is anti-inflammatory, it reduces the levels of inflammation in your body. If you have a cut or wound, then local inflammatory processes start to provide an immediate action. Since cortisol levels peak about 10-30 minutes after the start of the stressor this allows initial inflammation processes to take place before cortisol takes it’s hold
• Cortisol can help regulate blood pressure and blood sugar
• Cortisol is involved in managing your bodies use of carbohydrates, fats and proteins
• Critically, cortisol also acts on the hypothalamus to downregulate the release of CRH and ACTH. This prevents the cycle of CRH-ACTH-Cortisol from continuing endlessly

Question 16

Give features of the hypothalamus and Bard’s 1928 experiment about it

Answer 16

• Located centrally in the brain
• Promotes a balance or homeostasis
• In 1928 Bard reported a series of studies where he removed a large part of cerebral cortex either with or without the hypothalamus. He observed that when the hypothalamus was left intact, but without the frontal cortex that normally constrains behaviour the animals would fly into a rage showing the role of the hypothalamus in the fight or flight response

Question 17

What does the pituitary gland do?

Answer 17

• It releases hormones involved in growth (such as human growth hormone), in metabolism (TSH), fertility and stress response (ACTH)
• ACTH circulates through the blood and is detected by the adrenal gland

Question 18

What does the adrenal medulla do in response to stress?

Answer 18

It is involved in stress responses but releases a different hormone which acts much faster than cortisol (seconds to minutes rather than 30 minutes)

Question 19

When activated what does the sympathetic nervous system do?

Answer 19

• It causes blood vessels in deep tissue to dilate to increase blood flow to muscles
• It causes blood vessels in superficial tissue like skin, to constrict, which is why faces drain of colour when frightened
• It stimulates the adrenal medulla to release adrenaline, which further increases the effects of the sympathetic nervous system and dilates the pupils
• In the brain a similar hormone, noradrenaline is released from a nuclei called the locus coeruleus. Noradrenaline acts on a number of brain structures and effects cognition by enhancing attention

Question 20

What is Hans Selye’s general adaption syndrome?

Answer 20

• He did experiments on rats and found that chronic exposure to stressors led to a sequence of 3 stages:
• alarm
• resistance
• exhaustion

Question 21

What happens during the alarm stage?

Answer 21

 Arousal of the ANS
 Primarily during first encounter with stressor: resistance to stressor drops below normal with potential for shock
 At this point, hormones like epinephrine and cortisol are released from the bloodstream
 Sympathetic nervous systems are activated

Question 22

What happens during the resistance stage?

Answer 22

 Continued exposure to stressor
 Resistance – parasympathetic system returns physiological functions to normal levels
 Blood glucose, adrenaline and cortisol all remain high
 Heart rate, blood pressure, breathing all increased
 Over time resistance to stressor increases, levels out at normal levels
 Resistance = adaptation to environmental stressors

Question 23

What happens in the exhaustion stage?

Answer 23

 If the stressor continues beyond the body’s capacity, the stressor depletes the available resources
 Loss of ability to adapt to situations
 Susceptible to illness and even death