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Chapter 16

PSYA02H3 Chapter Notes - Chapter 16: Frontal Lobe, Adrenal Gland, Posttraumatic Stress Disorder


Department
Psychology
Course Code
PSYA02H3
Professor
John Bassili
Chapter
16

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Chapter 16 – Lifestyle, Stress and Health
Lifestyle choices and Consequences
Cultural evolution: a cultures adaptive change to recurrent environmental pressures
driven mainly by psychological forces
Its a product of human intellect and physical capacity which have genetic
components
Cultural evolution has been the primary agent involved in shaping lifestyle
Lifestyle: the aggregate behavior of a person; the way they lead their life
Today there is no predominant lifestyle like there was for prehistoric ancestors -
cultural evolution has allowed us to have the luxury of choosing among alternatives
Cultural evolution has resulted in a much higher standard of living than ancestors but
has caused health and safety threats
Although the consequences of unhealthy lifestyle behavior (excessive drinking) have
obvious negative biological implications, the behaviors themselves can be acquired
and maintained by both biological and psychological factors
The law of effect: Behaviors that produce favorable consequences tend to be repeated
and those that produce unfavorable consequences tend not to be repeated
Many unhealthy behaviours have reinforcing consequences in the short run and
damaging consequences in the long run - enjoy now, suffer later
Short term benefits with long term consequences
*interim summary p.528*
Stress and Health
Stress: a pattern of physiological, behavioural, emotional, and cognitive responses to
real or imagined stimuli that are perceived as blocking a goal or
endangering/threatening our well-being
Stress is a response to something that is challenging in the environment (a stressor--
something challenging in the environment).
Stressors: aversive stimuli that are perceived as endangering ones well being; they
cause stress
Stress is a product of natural selection (behavioural adaptation that has helped us fight
or flee from enemies)
It helps us confront or escape threatening situations
Stressors come in many forms from natural catastrophes to everyday irritators; but
they’re not always bad (like stress from athletic competition and class exams) and can
affect behaviour in positive ways
If its extended over a long period of time it can have health effects psychologically
and physically
The Biological Basis of Stress
Our physical response to stress is governed by our autonomic nervous system which is
controlled by the hypothalamus
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Stress is a biological response that is experienced as an emotion
When an individual senses a stressor, the hypothalamus sends signals to the
autonomic nervous system and to the pituitary gland, which respond by stimulating
body organs to change their normal activities:
1. heart rate increase, blood pressure rises, blood vessels constrict, blood sugar levels
rise, and blood flow is directed away from extremities and toward major organs
2. breathing becomes deeper and faster and air passages dilate which permits more air
to enter the lungs
3. digestion stops and perspiration increases
4. the adrenal glands secrete adrenalin (epinephrine) which stimulates the heart and
other organs
These changes prepare the body to deal with the stressor
these physiological responses produce a heightened psychological and physical state
of alertness and readiness for action
VIDEO: when a threat situation is seen, the area of the brain known as the cortex
recognizes the lion, and the msg is sent throught to the amygdala, the amygdala then
activates the hypothalamus in the base of the brain (hypothalamus is the critical part
of the brain that organizes the message and sends signals which get to the adrenal
gland and releases adrenalin. Also sends other msgs to the pituitary gland and this
makes cortisol.
however there are 2 cases in which stress can be maladaptive:
1. stress can produce anxiety, which may impair ones ability to perform a task
2. the effects of prolonged and severe stress - our lifestyles place us in situations in
which were confronted with stressors daily; these lifestyles put us at risk of illness
Selyes General Adaptation Syndrome
He worked with lab animals and found the following:
General Adaptation Syndrome (GAS): Chronic exposure to severe stress produces a
sequence of 3 physiological stages: alarm, resistance, and exhaustion
Alarm: involves arousal of the autonomic nervous system and occur when the
organism is first confronted with a stressor
during this stage the organisms resistance to the stressor temporarily drops below
normal, and they may experience shock - impairment of normal physiological
functioning
With continued exposure to stressor, organism enters stage of resistance
Resistance: continued exposure to the stressor, the autonomic nervous system returns
to normal functioning
Resistance to the stressor increases and plateaus at above-normal levels
Resistance is a reflection of the organisms adaptation to environmental stressors
With continued exposure, we get exhaustion
Exhaustion: the organism loses its ability to adapt, and resistance plummets to below-
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normal levels, leaving the organism susceptible to illness and even death
Were able to adapt to the presence of environmental stressors for only so long before
we become susceptible to exhaustion and illness
Emotional responses are designed primarily to cope with short-term events
The physiological responses that accompany the negative emotions prepare us to
threaten or fight rivals or to run away from dangerous situations
Fight or Flight Response (Walter Cannon): the physiological reactions that prepare
us for the strenuous efforts required by fighting or running away
If the threatening situations are continuous rather than episodic (short-term), they
produce a continuous stress response - this continued state of arousal can lead to CHD
and other physical problems
Physiological Mechanisms Involved in Stress
Emotions consist of behavioural, autonomic, and hormonal responses - the latter two
are the ones that affect health
The sympathetic branch of the autonomic nervous system is active when there are
threatening situations that call for vigorous activity
The adrenal glands secrete epinephrine, nor epinephrine, and steroid stress hormones
Epinephrine releases the stored form of glucose that is present in the muscles, thus
providing energy for strenuous exercise
-increases blood flow to muscles
-release of glucose in muscles
-increase blood pressure
Along with Norepinephrine, it also increases blood flow to the muscles by increasing
the output of the heart, which increases blood pressure
Over long term, these changes contribute to CHD
The other stress-related hormone is called cortisol : a steroid secreted by the cortex of
the adrenal gland
Glucocorticoid: a chemical such as cortisol, that has profound effects on glucose
metabolism (benefits that of cortisol above)
-increase glucose utilization
-turns protein into glucose
-liberation of fats for energy
-stimulate behavioural responsiveness (by affecting the brain, presumably)
-increase blood flow
They help an animal react to a stressful situation but they also help it survive
When adrenal glands of rat are removed, the rat is much more susceptible to negative
effects of stress
Although the short-term effects are essential, the prolonged secretion of
glucocorticoids are damaging (increased blood pressure, damage to muscle tissue, one
form of diabetes, infertility, stunted growth, inhibition of the inflammatory responses,
and suppression of the immune system)
Children exposed to high levels of stress main not attain their full height
Inhibition of the inflammatory response makes it more difficult for the body to heal
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