pattern of physiological, behavioural, & cognitive responses to stimuli (real or imagined) that disturb equilibrium & tax or exceed our ability to cope
physical and psychological responses to internal or external stressors
Stress Definition - physiological, behavioural, cognitive responses?
- physiological = real event in body: lungs are working harder, adrenaline, immune system producing corticosteroids
- Behavioural: running, fighting, moving quicker
- Cognitive : attention focuses, narrows on what you have to deal with – can’t notice things outside of it
- specific events or chronic pressures that place demands on a person or threaten the person’s well-being
- aka what causes stress – can be an earthquake, a person, etc
how psychological factors influence the causes and treatment of physical illness and maintenance of health
Levels of Stress: hassles vs stress?
- Hassles: small stress like losing keys, social obligation you don’t want to go to, not sleeping well, environmental noise
- Duration is what differentiates it from stress: hassles have same effect as stress, but lasts shorter
- Stress: prolonged exposure to something taxing
- stressful events that occur continuously or repeatedly – PTSD
- ex: Strained relationships, financial problems, etc
- Small stressors easy to ignore if they happen occasionally but accumulate to distress and illness
- More symptoms and greater and longer lasting impact than major life events
- Many are linked to particular environments – ex. city life
Percieved control - study by who?
Glass & Singer (1972) did studies of perceived control: aftereffects of loud noise on people who could or couldn’t control it
Fight or flight response
- autonomic NS - sympathetic
- emotional and physiological reaction to an emergency that increases readiness for action
Nervous vs Endocrine System
- NS: rapid responses
- Endo: slower, more gradual and more sustained
Endocrine System - purpose, what?
- Regulates mood, growth, metabolism, sexual and reproductive processes
- System of glands that secretes hormones that go directly to bloodstream
like NT, but NT travel small distances
hormones travel from one part of body to another
type of hormone released by adrenal gland during stress
biochemicals indicating activation of emotional systems
Amphetamines inhibit breakdown of catecholamines
Immune system - what and purpose?
- defense system
- fight invading bacteria/viruses
- Complex response system that protects the body from bacteria, viruses and other foreign substances
Antigen vs Pathogen
- A: protein on surface of cell
- P: invading bacteria
- threat activates hypothalamus
- hypothalamus secretes CRH which stimulates pit gland
- pit gland releases ACTH which stimulates adrenal gland
- adrenal gland secretes hormones
HPA axis - adrenal gland secretes? (2)
- Cortisol, a major stress hormone - increases concentration of glucose in blood so muscles have fuel, also dampens immune system by muting white blood cells
- Catecholamines: epinephrine and norepinephrine - increase sympathetic NS (increase heart rate, blood pressure, respiration) so more oxygen is available to muscles for attack/escape
- studied physiological consequences of severe threats to well being
GAS - general adaptation syndrome
- description of the body’s short term and long-term reaction to stress
- three stage physiological stress response that appears regardless of the stressor that is encountered
- nonspecific so response doesn’t vary according to source of repeated stress
Selye's Three Phases of Stress Reponse?
- Alarm reaction - mobilize resources
- resistance - cope with stressor
- exhaustion - reserves depleted
GAS - phase 1
Body rapidly mobilizes resources to respond to threat – aka fight or flight lasts only a few seconds
muscles clench, heart rate and breathing increase, more blood sent throughout body
GAS - phase 2
- Resistance Phase
- Body adapts to high state of arousal, tries to cope with stressor and maintain homeostasis
- continues to draw on resources of fat/muscle, release of hormones, blood sugar, blood pressure stays high
- stops unnecessary processes like digestion, growth, sex drive, menstruation, testosterone/sperm production
GAS - phase 3
- Exhaustion Phase
- body depleted of resources, resistance collapses
- Resistance phase defenses created gradual damage = costs for body like susceptibility to infection, tumor growth, aging, organ damage, death
- Can still recover from this stage but will take longer than if stressor had ended at stage 2
Is stress always bad?
sometimes you need a quick burst of speed
shot of adrenaline
stress gives you energy, vigilance and attention
Stress bad because?
prolonged stress can lead to anxiety and poorer performance (while a little bit of stress helps performance)
can lead to chronic heart disease, increased risk of heart attack, damage to heart tissue, stunted growth, infertility, supresses immune system
Hans Selye – there are two kinds of stress?
Eustress: positive stress like having a baby, getting married, graduating
Distress: what we think of when we think of stress – negative stress
Causes of Stress - what do they have in common?
Majority of the things are psychological in nature = in our heads, not in the real world
That means 5/7 major stressors are unique to us as a species
Stress and Immune System: phagocytes? lymphocytes? glucocorticoids?
Phagocytes: neutrophils that are first on the seen, attach to antigens and destroy them
Lymphocytes: produce antibodies that fight infection (T cells – rupture cell and B cells)
Glucocorticoids flood the brain – wears down immune system so less able to fight invaders
Physical vs Psychological Stressors
Physical stressors: colds, bacterium, viruses - make us more likely to get sick
Psychological stressors: inside our head, can be a result of for example, taking care of someone with a chronic disease
Baboons - major stressor? perfect model? our stress is different?
Each other – other baboons
perfect model for western stress-related disease because a lot of our stress is social in nature, not physical
- How is our stress different from the stress of other animals, like zebras?
o They can turn it off after – we are constantly worrying
- Examples of studies
o Medical volunteers received mouth wounds – healed slower during exams than summer
o Researchers swabbed cold virus into volunteer’s nose – people got colds depending on stress levels volunteers who had experience chronic stressors more likely to suffer colds
o Social status and health: British civil servants with higher status had lower rates of death
o People who perceive themselves in lower social status are more prone to suffer from respiratory infection
Examples of studies - stress and mouth wounds? colds?