7) Stress 1 Flashcards
Define what is meant by a ‘stressor’ and ‘stress reactivity’
Stressor- stimuli that causes physiological/psychological change to our stress system SNS
Stress reactivity- the ways we respond to stressors
What effects might chronic stress have on the body?
Key changes in body muscles- a state of guardedness
Tension type headaches
Long term heart problems- hypertension/heart attack
Give the key finding from Everson-Rose’s multi-ethnic study measuring stress levels across 5 domains
Those experiencing stress had a 10% greater risk of experiencing, even when confounds were accounted for
What term did Walter Cannon first term
The ‘fight or flight’ response.
- Short term arousal > heightens system > physiological changes
What are the 3 key areas that can cause stress
Psychological, physical and social (can be either acute or chronic
The HPA axis of the stress response involved which 3 structures
(H) Hypothalamus (P) Pituitary gland, in brain just below hypothal (A) Adrenal Gland, just above the kidney
The HPA axis links which body systems - what is it’s key function?
The endocrine system- responsible for metabolism, growth, development linked with the nervous system
Provide the key stages in the HPA stress response
1) Stressro triggers a response
2) The hypothalamus secretes CRH (corticotrophin releasing hormones).
Passes through the anterior pituitary gland
3) CRH then stimulates the synthesis and secretion of ACTH into the blood stream
4) It then passed down into the adrenal gland above kidney (of the adrenal cortex)
5) This then stimulates release of cortisol (anti-inflammatory) - main purpose of working to calm down the stressed system
Where is the hypothalamus located and what is it’s key function
Located centrally below the thalamus, and is part of the limbic system. It key role is linking the endocrine with the nervous system via the pituitary gland as well as several homeostasis process i.e. thermoregulation, circadian rhythms, satiety.
Located beneath the hypothalamus and releases corticotrophins (CTH, ACTH), thyrotropins (thyroid in neck. What is this structure?
The pituitary gland
Releases adrenaline/ cortisol in response to ACTH secretion, metabolism/immune system changes. Located above kidney. What structure is this?
The adrenal gland
Name the syndrome when you have too MUCH cortisol
Cushing’s (remember cushion, much soft) syndrome- rapid weight gain, acne, reduced libido, infertility, chronic tiredness
Addison’s disease (symptoms like weight loss, weakness/lethargy) is what kind of syndrome?
Having too LITTLE (think ‘need to ADD more- ‘ADDison’) cortisol in your system
Adrenaline released in the adrenal gland (above kidney) has what key functions
- Prepares the ANS for organ activity once hormones are released i.e. pupils dilate, dry mouth, increased heart rate
(simply, most system features HEIGHTEN) - Adrenaline releases the stored form of energy in muscles (protein»_space; glucose)
- Involved in the 4 F’s (fight, flight, food, fornication)
Aside- Where is the source of noradrenaline production (not part of SNS, part of PNS)
The Locus Coeruleus
Give the key role of the PNS
Returning the body back to it’s normal state, calms and relaxes. i.e. pupils constrict, reduced heart rate, normal salivation
Explain the 3 stages of Han’s Selye’s GAS
1) Alarm stage:
Arouses ANS on stressor first encounter. Adrenaline released into bloodstream and SNS activated
2) Resistance stage:
Continued exposure to the stressor. PNS returns physiological function back to normal.
Over time resistance to stressor increases, activation of PNS to stressor levels off.
3) Exhaustion Stage:
If stressor continues beyond body’s capacity, it drains the body’s resources and lends to greater illness susceptibility
What does Berns’ neurobiological study of dread tell us about stress
The evidence shows often the stress of waiting for something can be worse than the experience itself.
Those who felt they had more ‘dread’ would opt for the higher shock level over a shorter period to get it over with
Give a few benefits of stress
Sharpened cognition, energy mobilised, increased cardiovascular activity, growth
What are typical disorders of stress (effect on growth/ chronic stress & brain structure
- Fatigue, diabetes, hypertension, peptic stomach ulcers, neuron death.
- Stress dwarfism- effects body growth. Orphan boy grew rapidly out of stressful home, but this again halted when his favourite nurse left for a period, before returning to normal again when she returned.
- Reduced number of neurons in the hippocampus of rats with chronic stress induced vs controls
What is the body’s immune system derived of for protection against invading bacteria, viruses, foreign bodies
White blood cells in- bone marrow (B lymphocytes), thymus gland (T lymphocytes)
Give study examples of stress effect on immune system
1) RATS- Keller induced inescapable shock to rats which gave them chronic stress and weakened their immune system (reduced B & T cell count)
2) RATS ULCERS-
When rats were given more objects/wood to gnaw on , wheel for running = fewer stomach ulcers (frustration outlet)
3) RATS- when given a warning about incoming shocks they also had fewer ulcers (sense of predictability)
4) EXAMS-
Student sample saw weakened immune systems with greater risk to infections like mouth ulcers during the exam period
5) OLD PEOPLE-
When given more choice in an old people’s home, that group after a period were healthier, happier, more active, alert and half as many as control died
6) SPOUSE-
Those with a spouse live longer (act as buffer), risk of dying only increases if you’re a male widow, no different for females.
