Download Stress and the Immune System

How and Why Do We
Experience Stress?
The human stress response to
perceived threat activates
thoughts, feelings, behaviors,
and physiological arousal that
normally promote adaptation
and survival
Copyright © Allyn & Bacon
2007
Stress and Stressors
• Stress
Stressor
A
stimulus
• stressful
A physical
and
…. a condition
mental
response to
demanding or
a challenging
adaptation
threatening
situation
Primitive Stressors
1. Starvation
2. Exposure to the
elements
3. Mortal attack
4.
•
Humans who respond
more quickly to danger
survived
A Model of Stress
Traumatic Stressors
• A situation that
threatens one’s
physical safety,
arousing feelings of
fear, horror, or
helplessness
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Catastrophe
Copyright © Allyn & Bacon 2007
Cohen and Ahearn
•
Identified five stages that occur in the wake of natural
disasters
1. Psychic numbness: Shock, confusion
2. Automatic action: Little awareness/recall of the
experience
3. Communal effort: People pool resources and
collaborate
4. Letdown: Depletion of energy, feel abandoned
5. Recovery: Survivors adapt to changes created by
the catastrophe
Copyright © Allyn & Bacon 2007
Post-Traumatic Stress Disorder
• Delayed stress reaction in which an
individual involuntarily re-experiences
emotional, cognitive, and behavioral
aspects of past trauma
Copyright © Allyn & Bacon 2007
The Physical Stress Response
•
1.
2.
3.
4.
The physical response to nearly any stressor
follows the same sequence.
Initial arousal
Protective behavioral reaction, often fight-orflight
Internal responses to the autonomic nervous
system and endocrine system
Decrease in the effectiveness of the immune
system
Copyright © Allyn & Bacon 2007
The Physical Stress Response
• Arousal: Increased physiological state
Copyright © Allyn & Bacon 2007
The Physical Stress Response
• Acute Stress
A temporary pattern of arousal caused by a
stressor with a clear onset and limited
duration
• Example: flashing blue lights in your
rearview mirror
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The Physical Stress Response
• Chronic Stress
A continuous state of stressful arousal
persisting over time
• Example: A bad marriage
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The Physical Stress Response
• Fight-or-Flight Response
A
sequence of internal processes that prepares
the organism for struggle or escape
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The Physical Stress Response
• Withdrawal:
If fight or flight is not possible, or
stressor is too much to handle, the
organism may ‘freeze’
• Ex: Deer in the
headlights
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The Physical Stress Response
• Passive Fear Response:
• An individual responds to a threat
by becoming emotionally
withdrawn and disengaged.
• Example: A rabbit, instead of
running, eludes a predator by
hiding or remaining still
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The Physical Stress Response
• Tend-and-Befriend Model
• A stress response model
proposing that females
are biologically
predisposed
to respond
toof stress is vital to ensuring the
Tending
to offspring
in times
stress by nurturing
and of the species.
survival
protecting
offspring
(tend) biological stress responses in
Tending
activities
also reduce
• and seeking out
a social
both
parents and offspring,
group for joint protection
(befriend)leads to substantial mental and physical health
Befriending
•
Does
notin replace
the
benefits
times of stress.
“Fight or Flight” response
Copyright © Allyn & Bacon 2007
The General Adaptation Syndrome
(GAS)
• A pattern of responses to any serious
chronic stressor
• Prolonged stressor response can contribute
to heart disease, ulcers, arthritic, asthma,
even death
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General Adaptation Syndrome
G. A. S.
3 Stages
1. Alarm
2. Resistance
3. Exhaustion
Healthy Adaptation or Illness
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Stage One - Alarm Reaction
Sympathetic
•--Mobilize
1. Body mobilizes
its
resources
to
cope
with
a
energy from stores, inhibit further storage
stressorInhibit digestion, growth, reproduction, immunity
HR, BP, breathing
• 2.--Increase
Hypothalamus
sets off a response through
--Fight
or flightsystem
response
the
endocrine
--Analgesia
• 3. Adrenal hormones are released
--Aspects of senses and memory improve
• 4. The sympathetic nervous system is
activated
IF STRESSOR IS NOT REMOVED IN TIME,
THE ORGANISM MOVES TO NEXT STAGE
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Stag Two - Stage of Resistance
• Arousal (Alarm reaction) subsides
Resistance
• The parasympathetic
system activates adrenal
output
Bodyslows
tries to adapt to stressor
Hormonal changes to cope with
• If a second stressor is introduced, the
stress
organism may not be able to adapt
Conservation of resources
IF STRESSOR IS NOT REMOVED IN TIME,
Effects
on activity
feeding
THE ORGANISM
MOVESlevel,
TO NEXT
STAGE
etc.
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Stage Three - Stage of Exhaustion
• Organism tires fighting stressor
• Symptoms of Alarm Stage (Stage One)
reappear
• Parasympathetic system overcompensates in
an attempt to stop surging hormones
IF STRESSOR DOES NOT DISAPPEAR IN TIME
DEATH OCCURS
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The General Adaptation Syndrome
Alarm
reaction
– the body
mobilizes it’s
resources to
cope with a
stressor
Level of
normal resistance
Alarm Reaction
Resistance
– the body
seems to adapt
to the presence
of the stressor
Exhaustion
– the body
depletes it’s
resources
Successful Resistance
Illness/death
Resistance
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Exhaustion
Stress and the Immune System
•
The human immune system
response, which evolved to
respond to short-term
stressors, may react to
chronic stressors by breaking
down and turning on itself
Copyright © Allyn & Bacon 2007
Stress and the Immune System
• Psychoneuroimmunology
cytokines
Multidisciplinary
field
that studies
thereleases
After
they alert the brain
to distress,
the brain
influence
of mental
states
onoutput,
the immune
its own
cytokines
to reduce
energy
causing
systemlike fever or listlessness, responses that
symptoms
usually help fight disease
• Cytokines
(site-toe-kines)
Also may cause depression, prolonging stress and illness
• Hormone-like chemicals facilitating
communication between brain and immune
system
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Personality Types and Stress
• Type A –
•
behavior pattern characterized by intense,
angry, competitive, or perfectionist
responses to challenging situations
• Type B –
• behavior pattern characterized
by a relaxed, unstressed
approach to life
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Type A
– Highly driven
– Competitive
– Impatient
– Aggressive
– Feel rushed and
under pressure
– Find it difficult to
give up control or
power
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Type B
– Relaxed
– More
focused on
the quality
of life
– Less
ambitious
and less
impatient.
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Psychological Responses to
Stress
• Learned Helplessness
Passive resignation following reoccurring
failure or punishment
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Resilience
• Capacity to adapt, achieve well-being, and
cope with stress, in spite of serious threats
to development
Copyright © Allyn & Bacon
2007
End of Chapter 8