3 - stress and illness Flashcards
examples of common stressors
small daily hassles e.g. missing the bus academic or work related concerns e.g. exams relationship issues financial problems loss of control over goals
factors that make an event stressful
perceived as negative
lack of control
long-lasting
cannot be dealt with using current resources
amiguity
relevant to important life domains/aspects of self
transactional theory (Lazarus and Folkman)
define stress as..
“a relationship between the person and environment that is perceived by the person as taxing or exceeding his or her resources and endangering his or her wellbeing”
factors affecting how stressful an event is for an individual
appraisal differences (perception of the stress) psychological differences coping mechanisms --> strategies to deal with the stress
example of a way to measure stress
the social readjustment rating scale (Holmes and Rahe)
records how people rate different types of stress
measures daily hassles and uplifts
what are daily hassles
small difficulties during the day that may add up and create unmanageable demands
e.g. rising prices, noisy neighbours, too many responsibilties
what are daily uplifts
positive occurrences that may offset the daily hassles and reduce the perceived demand
e.g. good weather, getting on well with friends
how are hassles and uplifts measured in the social readjustment scale (Holmes & Rahe)
factors are rated on a scale of 0-3 of perception as a hassle or an uplift
examples included children, parents, partner, weather, news
results from social readjustment scale (Holmes and Rahe)
ratings of factors from hassles to uplifts varied from day to day
more hassles were associated with lower social wellbeing
daily uplifts made little difference
hassles were found to be good indicators of stress
how does stress directly effect your health
affects functioning of the cv and immune system
due to cortisol entering the bloodstream
chronic stress undermines general system functioning
how does stress indirectly affect your health
increases health risk behaviours e.g. smoking, alcohol use, drug use –> negative health consequences
decreases health promoting behaviours e.g. physical activity, good sleep, good diet
–> secondary consequences such as tiredness affecting eating habits, physical activity etc.
evidence to show that stress affects speed of wound healing
small biopsy wound in hard palate of dental students
taken once in summer holidays and once before major exams
healing resonse was measured as much longer for those in exam condition
physical effects of moderate/severe stress
dry mouth perspiration headaches high BP GI problems lower back pain
emotional effects of moderate/severe stress
anxiety depression fatigue irritability impulsiveness hypervigilance
cognitive effects of moderate/severe stress
inability to concentrate
memory problems
behavioural effects of moderate to severe stress
teeth grinding crying disrupted eating aggression sexual problems
how is stress induced by the nervous system
sympathetic nervous system
adrenal medulla releases catecholamines e.g. adrenaline to induce stress response
cortisol is released into the blood stream
physiological responses to sympathetic nervous system
bronchiole dilation increased breathing rate increased heart rate increased BP increased blood glucose decreased metabolism decreased digestion decreased immune activity and pain perception
physiological responses to the parasympathetic nervous system
reduces adrenalin secretion reduces heart rate and blood pressure reduces breathing rate reduces perspiration increases salivation body returns to homeostasis promotes relaxation facilitates energy storage
adrenal glands
sit on top of kidneys
pyramid shapes
made up of cortex and medulla
adrenal medulla
secretes catecholamines e.g. adrenaline, noradrenaline
adrenal cortex
outer section of adrenal gland
produces glucocorticoids
e.g. cortisol
2 nervous and endocrine mechanisms of stress response
sympathetic adrenal medullary (SAM) system
hypothalamic pituitary adrenal (HPA) axis
what does SAM stand for
sympathetic adrenal medullary system
what is the SAM system
initial response to stress (fast and moderate)
hypothalamus in midbrain releases corticotropin releasing hormone (CRH)
CRH enters blood stream and stimulates adrenal medulla to release adrenalin
what does HPA stand for
hypothalamic pituitary adrenal axis
features of the HPA axis
secondary stress response
slower with longer, more extensive effects
cortisol secretion into the blood
mechanism of HPA axis
hypothalamus releases CRH
CRH travels in blood stream to pituitary gland
adrenocorticotrophic hormone (ACTH) released
ACTH stimulates adrenal cortex to release corticoids and cortisol
effects of cortisol
increased protein and fat mobilisation
increased access to energy storage
decreased immune response
decreased inflammation
how does chronic stress cause illness
increased risk of viral infection
triggers histamines which lead to bronchoconstriction –> exacerbates asthma
increases risk of diabetes mellitus
alters acid concentration in stomach –> leads to pepti ulcers, ulcerative colitis
arterial plaque build up (atherosclerosis)
psychiatric illness e.g. depression, anxiety, schizophrenia
tumour development and NK cell suppression –> metastasis no longer prevented
how does chronic stress cause cardiovascular disease
leads to the continual release of catecholamines and corticosteroids
increases HR
increases BP
increased force on heart muscle walls and circulatory system
increased platelet count
increased growth of plaques
how does stress cause damage to the heart
heart muscle walls become enlarged and damaged
particularly left ventricle (main pumping chamber) –> LV hypertrophy
muscles lose elasticity –> cant pump with sufficient force
effects of damage to the heart caused by stress
shortness of breath fatigue chest pain heart palpatations dizziness increased risk of heart attack and stroke
effect of chronic stress on circulation
blood vessels and arteries become distended/inflamed due to increased blood flow
vessels become rigid (wrapped with more muscle)
fat and cholesterol attracted and forms plaques which can rupture causing blood clots
what happens in plaques formed on blood vessels rupture
stroke if occurs in the brain
myocardial infarction if occurs in the heart
blood clot if anywhere else
how can chronic stress lead to depression
high cortisol levels makes brain more susceptible to depression when stressed
evidence that stress is linked to depression
daily cortisol measured from 3 groups –> depressed group had higher morning cortisol levels and higher net secretion of cortisol in response to stressful task
what is autoimmunity
when the immune system attacks self-cells
what do vaccines take advantage of
the natural, non-specific response to pathogens
function of immune system
to recognise and destroy pathogens based on markers on their cell walls (antigens)
features of innate immune response
immediate
fast
general
phagocytes migrate from bloodstream to site of infection and consume pathogens
display pathogens on walls (antigen presentation)
features of adaptive immune response
secondary
specific
slow
B and T cells respond to the displayed antigens
antigen specific receptors required through cell multiplication
outline cell-mediated immunity
NK cells directly attack via toxin secretion
helper T cells and T cells secrete cytokines to stimulate other immune cells
B cells become plasma cells which produce antibodies
outline antibody mediated immunity
B cells attach themselves to a pathogen and produce specific antibodies
antibodies bind to pathogen receptors
- cause them to burst
- OR mark pathogen for other immune cells to kill
antibodies assist in formation of memory B cells
T helper cells produce B-cell growth factors casing B cell proliferation and inreased antibody production
effect of stress on immune system
initial effect
- activates immune system e..g acute stressor such as a wound to avoid potential infection
chronic stress
- glucocorticoid shrinks thymus gland decreasing cell-mediated immunity
importance of thymus gland in immunity
T and B cells formed there
how can you measure immune function
count B, T and NK cells in blood samples
- examine how rapidly cells proliferate
measure how much antibody our body cotrains against common antigens
measure production of antibody in response to ingested substance that produces antigens
main man in measuring immune function
what did he find
Glaser
collected blood from med students 1 month and 1 day before exams
found NK cell activity much lower 1 day before exams
overall effect of stress on illness
stress increases cortisol which causes immunosuppression increasing risk of illness
rhinovirus study to show stressful life events increases risk of illness
17 subjects exposed to rhinovirus
symptoms measured over 5 days
recent stressful life events recorded
greater number of stressful recent life events had occurred in those that developed colds
