Biological Psych 7: Stress (Lec 31) Flashcards
Persistent stress that is not resolved through coping or
adaptation results in…
Distress
Stress that enhances function is called…
Eustress
Give an example of an environmental condition disturbing homeostasis, and the bodies reaction to maintain it
Cold causes us to shiver
An event which disrupts homeostasis, anything which requires exerting effort is a…
stressor
The feedback centre for the body’s homeostasis system using part of the brain as a relay centre. Which part is it?
The hypothalamus
A causes B, B causes A.
A causes B, B inhibits A.
Which is negative and which is positive feedback?
negative feedback involves inhibition
If a stressor is maintained beyond the alarm phase, the ______ phase in the body’s feedback system kicks in. This eventually leads to exhaustion.
the resistance phase
As one of the first responses to the alarm phase, under control of the SNS (sympathetic nervous system), which hormone is released?
Adrenalin release
What is the difference between the sympathetic and PNS (parasympathetic nervous system)?
The SNS (sympathetic nervous system) is usually the first to kick in during stress response. The PNS (parasympathetic nervous system) acts to calm it down.
Name the 3 main hormones which are released by the ANS (autonomic nervous system), and their basic functions
- Acetylcholine: Triggers NA (noradrenalin) release
- Noradrenaline / Norepinephrine: arousal (excitatory)
- Adrenaline / Epinephrine: arousal
Dilating pupils, hairs standing on end are examples of…
The SNS (Sympathetic nervous system) reactions…
The LC (Locus coeruleus), the major nucleus fin the pons associated with physiological responses to stress and panic. It’s the main source of noradrenaline and is associated with arousal and vigilance. It’s main physiological purpose is to increase…
reaction speed
Emotional memories are more durable than non-emotion fused memories. What neurotransmitter pulsing through the brain is largely responsible for this?
Noradrenaline
What is the major role of the glucocorticoid hormones, when they diffuse throughout the body’s tissues?
-Increase the release of energy stores (fats or glycogen which are stored in muscles)
The glucocorticoids are part of which axis system?
The HPA axis
CRH (corticotropin releasing hormone) is in a positive feedback loop with which neurotransmitter?
Noradrenalin
Explain the overshoot of the parasympathetic response (‘B process’) using the pattern of affective dynamics
Parasympathetic response (B process) acts to suppress sympathetic response (A process).
When A process (sympathetic response) comes to an end, B process overshoots causing a dip before returning to baseline (homeostasis).
Explain the overshoot of the parasympathetic response (‘B process’) using the pattern of affective dynamics.
What happens to the aftereffect (B process) over time (repetition of same type of experience)?
Parasympathetic response (B process) acts to suppress sympathetic response (A process).
When A process comes to an end, B process overshoots causing a dip before returning to baseline (homeostasis).
Over time, the sympathetic response (B process) becomes more sustained
When glucocoritcoids are released, what do they suppress?
They suppress the activity of the hypothalamus and the release of further glucocorticoids (CRH- corticotropin-releasing hormone, and ACTH {adrenocorticotropic
hormone}, which stimulates the release of cortisol)
When noradrenaline is released into the synaptic cleft, it binds to post-synaptic receptors. Some is also the subject of reuptake. This noradrenaline which is taken back into the presynaptic neuron then binds to alpha 2 autoreceptors. What do these do? What kind of feedback system is this?
Alpha 2 autoreceptors inhibit the further release of noradrenaline. This is a negative feedback system.
The hippocampus, hypothalamus and cortex trigger the stress response and are also rich in glococorticoid receptors. During the resistance phase of the stress response, glucocorticoids bind to them. What does this cause?
How does this function, between the hippocampus, hypothalamus and cortex, under normal conditions?
Suppression of further glucocorticoid release
Under normal conditions, the hippocampus and the cortex project down to the hypothalamus (part of the HPA axis), which then suppresses further glucocorticoid release.
Cortisol is a _____ hormone and is released by the _____ glands. What family of hormones does it belong to, and where is it’s secretion controlled from?
a stress hormone, released by the adrenal glands. It’s a glucocorticoid and it’s secretion is controlled by the HPA (hypothalamic pertuitary axis)
Alpha blockers depend on receptivity for receptors. Describe the difference between alpha 1 and alpha 2 blockers.
Alpha 1 blockers tend to be relaxants or sedatives, whereas alpha 2 blockers block the blocking (inhibit the inhibiting) of alpha 2 autoreceptors on noradrenaline relase. Since they block the blocking, they allow more noradrenaline to be released, which is stimulatory, hence they can be antidepressant.
How do stimulants and anti-depressants often work with NA (noradrenaline)?
stimulants and anti-depressants often affect reuptake of NA
What are the effects of beta blockers? (Think opp to alpha 2 blockers)!
Beta blockers have a calming effect, reducing anxiety and effecting cardiac.
How did learned helplessness (by exposure to a controllable or uncontrollable stressor) effect mice when they are given CRF (Corticotropin-Releasing Factor, which effects the normal HPA stress response) during a ‘place preference’ experiment? Describe the behaviour of the mice which were and weren’t exposed to a learned helplessness procedure. All mice were given CRF.
What does this show about the relationship between physiological and emotional responses?
The mice which weren’t exposed to a learned helplessness procedure prefered the part of the cage where they had been given the CRF (corticotropic releasing factor), because a small amount of stress response, under normal conditions, is enjoyable (think roller-coaster rides).
However, the mice that had been exposed to a learned helplessness procedure avoided the part of the cage where they were given the CRF, they developed an aversion to the stress response.
This shows that identical physiological responses can be associated with completely different emotional responses.
Depression is associated with chronically elevated glucocorticoids. Why is this hypothesised to take place?
Give an experimental example of how this was shown, using DMX (Dexamethasone)
The popular theory is that there is a loss of the negative feedback system in the HPA axis for those who suffer depression.
DMX (dexamethasone) is a glucocorticoid receptor agonist. This means that it suppresses cortisol (a glucocorticoid) release, however, it has very little effect on people with depression.
What happens to the hypocampus in people diagnosed with depression? Explain how this takes place, and it’s effect on neurogenesis (growth of new neurons).
The hippocampus shrinks. Glucocorticoids are important for inhibiting the stress response. Stress hormones are thought to shrink hypocampus.
This reduced hippocampus size in turn makes it harder for the hippocampus to inhibit the stress response, creating a vicious cycle.
The reduced size also depletes neurogenesis.
How can neurogenesis be promoted? Name 5 ways
Neurogenesis can be promoted by environmental enrichment, exercise, brain injury, abstinence of alcohol and antidepressant drugs.
How can neurogenesis be inhibited? Name 5 ways (3 are different drug types)!
Neurogenesis can be inhibited by:
Stress/ glucocorticoids x-rays alcohol nicotine cocaine and other stimulants
What is disregulation of the glucocorticoid response? Aslo known as loss of control of the HPA axis. Name the 2 factors contributing the the vicious cycle
Disregulation of the glucocorticoid response is explained by small hippocampus size and the reduction of glucocorticoid inhibition
Chronic stress also affects frontal regions of the brain important for emotional regulation: The anterior cingulate cortex (ACC), the posterior orbital
cortex and the ventrolateral prefrontal cortices (VLPFC).
Name the 2 post-mortem findings which help to explain this
- Loss of glial cells in these regions
2. Loss of dentritic branching and synapses between neurons in these regions
Depression effects areas in the amygdala, orbital cortex and prefrontal cortex in a different way than it effects the limbic cingulate cortex. Explain the difference in the 2 effects.
Depression causes increased activity in prefrontal areas but decreased activity in the limbic cingulate cortex.
The James-Lang theory purports that physialogical responses preceed emotional responses.
Describe the Schacter-Singer study which evidenced emotional appraisal.
How does this contribute to therapy techniques? Give an example.
People given adrenaline, not warned of any side effects and then exposed to positive or negative affect appraised the situation positively or negatively, reporting emotional responses of joy or fear.
Those given adrenaline but warned of side effects did not have the same emotional reactions, since they attributed the physiological response to the adrenaline they were given.
Cognitive reappraisal trains people to shift their cognitive perception of the physiological stress response, eg hyperventilation training trains people to cope with the hyperarousal by reducing negative association with the event.
What is the result of holding a strangers hand compared to your spouses hand during pain exposure?
Spouse caused largest reduction in ‘unpleasantness’, but bodily arousal reduced for both spouse and stranger hand-holding (still the most reduced with spouse hand).
Why might emotional memories be more enhanced than non-emotional memories?
Because the locus coeruleus sends a pulse of noradrenaline to the brain during the formation of that memory. This is thought to strengthen the synaptic connections
The main function of cortisol is to maintain the correct chemical balance in the during changes and adversity. Cortisol increases the production of ____ in the blood to boost energy during periods of prolonged stress. It also inhibits the ____ system
glucose
immune
Why do alpha blockers reduce stress?
Because alpha receptors, when stimulated, constrict the arteries to raise blood pressure. Blocking this process causes artery dilation.
Which neurotransmitter triggers the release of noradrenalin (NA), creating a +ve feedback loop where they continue to trigger further release of each other?
ACH -Acetylcholine
What’s the difference between adrenalin and noradrenalin?
Both act as neurotransmitters and hormones, but one is predominantly hormonal. Which is that?
Their target receptors. Adrenaline utilises alpha and beta receptors in the heart area, wheras noradrenalin affects the arteries (causing constriction and heightened blood pressure)
Adrenalin is predominantly hormonal, although small amounts are also produced by nerves as a neurotransmitter.
The PVN (paraventricular nucleus), is found in the _____, which is part of the ______ axis. It contains neurons which release _____ hormone as part of the stress response.
This process is a result of stimulation of the ______ receptors.
hypothalamus, HPA (hypothalamic pertuitary axis).
CRH (corticotropin releasing hormone)
This process is a result of stimulation of the glucocorticoid receptors.
