class 2 Flashcards
Stress is
a process involving perception, interpretation, response and adaptation to harmful, threatening, or challenging events
Perception of stress:
arises from events that cause stress
Stressors (e.g. excessive noise, pain)
Life events (e.g. new job, moving house, exams)
Interpretation of stress:
Cognitive and affective processes that
evaluate the stress, and the available coping mechanisms
this is a process of appraisal
Response to stress:
Biological responses and adaptations needed to cope with the stressor
Systems: GI, CNS, musculoskeletal, cardiovascular, endocrine, respiratory, other
Acute and chronic responses
Adaptation to stress:
Behavioral and cognitive response to the stressful event
Coping
e.g. changes in sleep patterns, eating habits, thought processes, changing priorities, etc.
So what
definition of stress was coined by Hans Selye, a Canadian endocrinologist
“the body’s non-specific response to any demand made upon it. It is not a disease but can contribute to ill health.” This definition refers to the body’s need to maintain homeostasis at all times.
positive aspects of stress.
Positive stress includes the normal physiological activity needed to maintain homeostasis, and the healthy emotional stress that makes life interesting & exciting. He calls this EUSTRESS.
negative aspects of stress.
Negative stress indicates the harmful effects of physical & emotional stress. An overload of stress from a situation of under or over arousal going on for too long produces first unpleasant feelings, and then physical damage and fatigue and ultimately even death. He calls this DYSTRESS.
Selye’s distinction is a valuable one. It recognizes the
inevitability and desirability of having some stress in your life while guarding against its ill effects. Manageable levels of stress, for reasonable duration, mobilize your resources and get you going on tackling the tasks and problems in your life.
STRESSOR:
potential triggers to the stress response (fight or flight); can be environmental agents/events, within or outside the body eg: physical effort, heat, cold, hunger, fatigue, pain, threats to self-esteem
STRESS REACTIVITY:
the body’s physiological response to the stressor; very individual; responses may be uncontrolled or excessive, not appropriate, or necessary to the trigger
duration of a stressor
a brief, acute event that does not recur:
the body’s response is rapid & efficient eg: jumping out of the way of an oncoming car
duration of a stressor
a series of stressful events that occurs as a result of an initiating event:
repeated stressful events which increase physiological responses; response may escalate over time; eg: job loss, can’t pay rent, car is repossessed, etc
duration of a stressor
chronic intermittent stress:
requires frequent responses to a regularly occurring stressor; eg: school exams, work deadlines
duration of a stressor
chronic & sustained stress:
continued exposure to stress depletes the body’s resources, allowing illness to take hold; eg: single parent trying to balance work, children, finances, etc
General Adaptation Syndrome (GAS)refers to
the 3 stages the body goes through, according to the DURATION of the stressor.
GAS stage 1: ALARM:
the first exposure to a particular stressor; cortisol levels are high
GAS stage 2: RESISTANCE/ADAPTATION:
if stress continues, the body tries to resist the stress & adapt to it; cortisol levels decrease as the initial alarm diminishes; the duration of this phase depends on the intensity of the stressor and the body’s ability to adapt; the ability to adapt will be decreased by lack of sleep, poor diet, working long hours
GAS stage 3: EXHAUSTION:
after long exposure to the stressor, the body’s adaptive energy is exhausted; signs of acute stress (the alarm phase) reappear
autonomic nervous system regulates the internal functions of the body and maintains homeostasis. It has 2 parts -
the parasympathetic system (rest and digest or feed and breed) and the sympathetic system (fight or flight).
Stimulation of the parasympathetic system results in:
reduced heart rate
constriction of pupils
stimulation of salivary & gastric glands
stimulation of peristalsis in the gut
stimulates urination by contracting bladder & relaxing urethral sphincter
Stimulation of the sympathetic system results in:
mental alertness to deal with danger
increased cellular metabolism
release of glucose from fat & liver for a burst of energy
increased heart rate, increased force of heart contractions
vasoconstriction in skin and abdomen to limit bleeding in case of injury
increased blood pressure due to vasoconstriction (above)
dilation of bronchioles to increase oxygen intake
dilation of pupils to increase visual acuity
inhibition of salivary & gastric glands (not essential if life is in danger)
Short term sympathetic stimulation is normal & is needed to deal with daily stressors. However, if the stressor is very intense, or if the stress lasts for long periods, sympathetic stimulation can lead to other health problems:
too much glucose can lead to diabetes
high heart rate & blood pressure can lead to heart attack
inhibited GI system leads to irritable bowel, constipation
The human body has a remarkable system to help us function when we are “under stress”. This is called the Stress Axis, or the
hypothalamic-pituitary-adrenal axis, and it was first described by Hans Selye.