Stress

Question 1

What is Stress?

Include study

Answer 1

Stress is “anything that throws your body out of homeostatic balance” (Sapolsky, 1994)

Question 2

What are the sources of stressors?

Name 3

Answer 2

1. Environmental (temp, noise)
2. physiological(food quality, water deprivation)
3. psychological (social subordination, novel situations)

Question 3

Why does perceptions matter with stress?

Answer 3

Because what is stressful to one may be pleasurable to another
stress causes arousal that is considered averisive (uncomfortbale and disliked sensation) Kim and Diamond, 2002

Question 4

What is the stress response?

Answer 4

1. physiological and behavioural responses that help to reestablish homeostasis
2. Upon perceiving a stressor, the hypothalamus signals neuronally to the adrenal medullae to secrete epinepherine (adrenaline) and norepinepherine(noradrenaline).
3. Norepinephrine: continuously released into the blood stream,narrows blood vessels to increaseblood pressure
4. Epinephrine: only released when stressed, itincreases heart rate and blood pressure, blood flow to the muscles and brain, and aids the conversion of glycogen

Question 5

What is the result of epinephrine and norepinephrine being released?

Answer 5

they have stimulatory effectson the respiratory and cardiovascularsystems,increases blood flowto the muscles, and raises bloodglucose levels (“fight-or-flight-response”) -> readying the body for emergency/survival action

Question 6

What does the hypothalamus release after epinephrine?

Answer 6

the hypothalamus releases CRH (Corticotropin-ReleasingHormone), which stimulates ACTH(AdrenoCorticoTropicHormone) release from the anterior pituitarygland. ACTH stimulatesglucocorticoidssecretion from the adrenalcortex.

Question 7

What does CRH do?

Answer 7

CRH (Corticotropin-releasing-hormone) stimulates the release of ACTH (adrenoCortioTropic Hormone) from the pituitary glands

Question 8

What does ACTH

Answer 8

ACTH(AdrenoCorticoTropicHormone) releases from the pituitarygland because of the release of CRH from the hypothalamus. ACTH stimulatesglucocorticoidssecretion from the adrenalcortex.

Question 9

What is the HPA axis?

Answer 9

1. Hypothalamus
2. Pituitary
3. Adrenal
4. A stressor affects the body
5. Hypothalamus sends a neuronal signal to adrneal gland which releases adrenaline and noradrenaline (this is immediate fight or flight)
6. Then Hypothalamus releases CRH
7. This stimulates Pituitary to release ACTH
8. This causes the Adrenal gland to release glucocorticoids (Cortisol)
9. Cortisol is always regulated by hypothalmus and pituitary so how much CRH and ACTH is released, meaning it as a negative feedbakc loop as its always going up and down

Question 10

What are glucocorticoids ?

Answer 10

CORTISOL

Question 11

What does cortisol do in relation to stress?

Answer 11

• shut down or alter functions that get in the way of the fight or flight response such as digestive or reproductive systems, immune of growth systems too.
• although cortisol is known as the stress hormone, it doesnt just promote the stress response. It also helps the body recover from stress and prepare for more potential stressors

Question 12

What are the adaptive effects of the stress response?

Answer 12

Increased availability of energy
Increased oxygen intake
Decreased blood flow to organs not necessary for movement
Inhibition of processes not necessary for immediate survival, e.g. digestion, immune function, reproduction
Decreased pain perception
Enhanced sensory function and memory
Non-specific: exhibited by both predator and prey

Question 13

What is general adpatation syndrome (GAS)?

Answer 13

Stage 1: alarm reaction
Stage 2: resistance
Stage 3: exhaustion/onset of stress pathology

e.g. Selye, 1950: rats in low temperature conditions for
2 days (stressresponse: immune suppression, atrophy of lymph nodes)
2 weeks (adaptation)
2 months (death)

Question 14

What are some examples of the prolonged pathological effects of stress?

Answer 14

Fatigue
Inhibited growth and repair process of the body
Pepetic ulcers because of immune system supression
Loss of libido
Impaired disease resistance - can lead to cancer

Question 15

What are the bodys immediate stress responses?

Answer 15

• inhibited digestion
• inhibited growth
• inhibited reproduction
• altered immune function and inflammatory repsonse
• enhanced cognition

Question 16

What is the time point where short term effects of stress become long-term maladaptive effects ?

Answer 16

Exact time point is not known

Question 17

Do glucocorticoids (cortisol) have:
A : Activational effects on brain and behaviour
B : Organisational effects on brian and behaviour
C : BOTH

Answer 17

C - BOTH !

Question 18

Is glucocorticoid secretion under a negative or positive feedback loop and explain

Answer 18

NEGATIVE FEEDBACK LOOP
1. Hypothalamus releases CRH
2. CRH travels to pituitary, stimulating release of ACTH
3. ACTH stimulates adrenal gland to release glutocorticoids (cortisol)
4. As cortisol rises, this exerts negative feedback on the hypothalamus and pituitary glands, signaling to decrease the release of CRH and ACTH
5. This decrease is CRH and ACTH, adrenal glands reduce production of glucocorticoids, leading to decrease in cortisol levels in bloodstream

This negative feedback loop helps maintain an approproate balance of glucocorticoids in the body, if cortisol drops the inhibition is lifted allowing for increased scretion to again retsore balance - still a negative feedback loop.

Question 19

What are the effectors of early stressors?

2 things, both 1 word

Answer 19

• enduring
• irreversible

Question 20

Tell me about prenatal stress in rats and how this affects offspring?

Answer 20

1. Offspring of stressed preggo rats shows increased activation of the HPA axis
2. Elevated blood corticosterone concentrations as adults (Henry et al., 1994)
3. More likely to be anxious and to self administer drugs (cocain, amphetamines; deminiere et al., 1992)

Question 21

What does prenatal stress in humans cause in the offspring?

Answer 21

1. Reduced birth weight, developmental delays, attentional defiicts, hyperanxiety , impaired coping strategy and impaired social behaviours - Weinstock, 1997
2. 1940 invasion int he netherlands, lead to babies who were born after mothers experienced this whilst pregnant led to an increased incidence of schizophrenia - Van Os and Selten, 1998

Question 22

Neonatal stress in rats - effects on offspring

Answer 22

Early stressful experience affect reactions to stress in later life (stress immunization effect)
e.g. brief separation of rat pups from mother is mildly stressful
Upon return, mother will lick pups more
As adults, these rats pups are better able to cope with stressors than non-separated pups (Liu et al., 1997)
Moderate or severe stressors as pups lead to elevated stress responses (=less coping) throughout life (Rots et al., 1996)

Question 23

What does early adveristy in humans cause?

case study

Answer 23

Romanin orphanages : Bad conditions of malnutrition, sensory depravation, poor hygeiene, disease and low levels of social interaction
Result : likelihood of long term behavioural problems and ednocrine dysregulation increase with length of institutional experience

Question 24

Case study on duration of neglect and brain functioning :

Answer 24

Vanderwert et al., 2010
- time spent in orphanage linked to decreases in EEG alpha power which is associated with perception and attention
- placing children into foster care aids recovery but only if the child is below 2 years of age

Question 25

What type of relationship is there between stress and behaviour

Answer 25

Bidirectional - stress affects behaviour but behaviour can also affect the stress response.

Question 26

What are the four things stress response is affected by ?

Answer 26

1. Control
2. predictability
3. outlets for dealing with frustration
4. Habituation

Question 27

Study for how the stress response is affected by : control

Answer 27

Weiss, 1968: rats who could control the rate of electric shock showed lower glucocorticoid (cortisol) secretions than yoked control rats

longer explanation : In the study, one group of rats could control the duration of electric shocks they received by pressing a lever, while another group received the same amount of shocks but had no control over them; the shocks were delivered independently of their actions.

Weiss found that the rats who had control over the shocks exhibited lower levels of stress hormones like cortisol compared to the rats who did not have control. This suggests that the perception of control over a stressful situation can buffer the physiological stress response. This concept has significant implications for understanding stress and coping mechanisms in both animals and humans.

Question 28

Study for how the stress response is affected by : Predictability

Answer 28

Warning signals prior to shock reduce glucocorticoid concentrations
(Sapolsky, 1992).

longer explanation:
In his study, he observed that when animals were given warning signals prior to experiencing a stressor, such as an electric shock, their glucocorticoid concentrations were reduced compared to when the stressor was unpredictable.

This finding underscores the importance of predictability and control in mitigating the physiological stress response. When animals have some degree of warning or anticipation before a stressor occurs, they can initiate coping mechanisms that help modulate their stress hormone levels. This research has significant implications for understanding stress management and resilience in both animals and humans.

Question 29

Study for how the stress response is affected by : outlets for frustration

Answer 29

When rats are shocked, they show lower glucocorticoid concentrations if they can chew on a piece of wood (Sapolsky, 1992)

Yes, Sapolsky’s research in 1992 indeed revealed that when rats were provided with the opportunity to chew on a piece of wood during or after experiencing a stressor, such as being shocked, they exhibited lower glucocorticoid concentrations compared to rats who did not have access to the wood.

This finding suggests that engaging in certain behaviors, like chewing on wood, can serve as a form of coping mechanism that helps regulate stress hormone levels in response to a stressor. Providing animals with outlets for natural behaviors or activities that they find comforting or distracting can have a significant impact on their stress responses. This research underscores the importance of considering environmental enrichment and behavioral interventions in stress management strategies for animals.

“Leg swinging” in children reduces heart rate (Soussignan & Koch, 1985)
Yes, the study conducted by Soussignan and Koch in 1985 found that leg swinging in children was associated with a reduction in heart rate. This research provides insight into the physiological effects of certain motor behaviors on autonomic nervous system activity.

Leg swinging, a repetitive and rhythmic movement, appears to have a calming effect on children, leading to a decrease in heart rate. This finding suggests that certain motor activities can influence the body’s physiological responses, potentially contributing to stress reduction or relaxation in children. Understanding how such behaviors affect heart rate and other physiological parameters can be valuable for developing strategies to promote relaxation and well-being, particularly in pediatric populations.

Question 30

Study for how the stress response is affected by : Habituation

Answer 30

Learning that a stimulus originally perceived as a stressor is not a stressor
e.g. lots of public speaking!

Ursin et al.’s study in 1978 focused on the concept of “learned helplessness” and how repeated exposure to stressors can lead to changes in stress response. Specifically, the study investigated how rats responded to repeated exposure to inescapable stressors, such as electric shocks. Over time, the rats learned that they could not control or escape from the shocks, resulting in a state of learned helplessness where they exhibited behavioral and physiological signs of stress even when presented with escapable stressors in subsequent trials.

The concept you’re referring to, about learning that a stimulus originally perceived as a stressor is not a stressor, can be related to the idea of habituation or desensitization. In the context of public speaking, individuals may initially perceive it as a stressor due to fear of judgment or performance anxiety. However, with repeated exposure and positive experiences, they can learn that public speaking is not inherently threatening, leading to reduced stress responses over time.

While Ursin et al.’s study focused on rats and learned helplessness, the concept of learning to perceive formerly stressful stimuli as non-threatening can apply to various situations, including public speaking, through processes such as habituation, cognitive restructuring, or exposure therapy.

Question 31

What are the individual differences in cortisol levels?

Answer 31

Perception of the stressor
Age - cortisol higher in 60+
Gender - Men show higher cortisol levels in repsonse to challenge than women
Nicotine - Smoking permanently alters the HPA axis and significantly increases salivary cortisol levels
Caffeine - stimulates ACTH release and increases cortisol levels