HLTC22H3 Chapter Notes - Chapter 10: Role Theory

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Published on 12 Apr 2011
School
UTSC
Department
Health Studies
Course
HLTC22H3
Professor
A&G: Chapter 10
Stress, Coping, and Health
Stress is a major pathway through which psychosocial factors affect physiology and the aging
process.
Through the Neuroendocrine system, psychosocial stress can have adverse effects on the
cardiovascular and immune systems.
Older adults may be vulnerable to the effects of physical stress
Evidence that stress can toughen or strengthen us through heat shock proteins and social ties
Genetic based mechanisms that protect against stress at the cellular level: DNA repair mechanisms,
antioxidants, and heat shock proteins
Stress
Three different major ways to describe stress:
1) Stress as a Physiological State
Classic Theories
Cannon (1915) was the first physiologist to systematically describe the physiological effects of
stress. He noted that cats exposed to barking dogs would respond with a rush of epinephrine or
adrenaline into their systems.
The sympathetic nervous system (SNS)- reacts to stress in two ways
Originates in the spinal column (preganglionic nerves) and radiate to the target organs
(postganglionic nerves)
Preganglionic are cholinergic they secrete the neurontransmitter aceteylcholine
Postganglionic nerves use norepinephrine
Sympathetic nerves works on the: the heart, bronchi, gut, kidney, blood vessels, sweat glands
and piloerector muscles
In sympathetic/adrenal medulla (SAM)- nerves radiate to adrenal medulla- which secretes
epinephrine (adrenaline) and norepinephrine (noadrenaline) into blood [stimulates organ
muscles and blood vessels]
Epinephrine- more powerful cardiac stimulant, increases metabolic rate
Norepinephrine- stimulates the peripheral vascular system & raises blood pressure
Sympathetic activation- increases heart rate, respiration rates, dilate pupils, diverts blood
flow & increases blood pressure [readies organism for physical activity]
Parasympathetic NS- brings the body back to homeostasis after stress or strenuous physical
activity
Prolonged increases in blood pressure and blood clotting would eventually result in
hypertension and cardiovascular disease
Hypothalamus secrets corticotrophin-releasing hormone (CHA)which activates the
posterior lobe of the pituitary
Pituitary releases adrenocorticotropin hormone (ACTH) into blood stream
ACTH stimulates the cortex of adrenal glands to release corticosteroids [glucocorticoids]
Cannon argued that this fight/flight reaction, although adaptive in the short run, could have very
harmful effects if prolonged.
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Hans Selye expanded on Cannon’s conceptions in two ways. First, he noticed that corticosteroids,
which are released by the adrenal cortex (or top layer of the adrenal glands), are also elevated in
response to a wide variety of stressors.
Glucocorticoids are fat-soluble molecules, which enables them to cross cell membranes in every
organ system in the body. Thus, they have a wide range of effects. Thus, stress can affect the
functioning of nearly every organ system in the body, either through SNS or HPA activation.
Second, Selye expanded Cannon’s dualistic processes (SNS vs. PNS activation) by describing three
stages in reaction to stress.
oThe alarm stage is similar to Cannon’s fight/flight reaction but involves the adrenal glands as
well as SNS activation.
oThe second stage was adaptation- in which there is a return to physiological homeostasis (due
to PNS activation)
oThird stage, exhaustion, the organism may fall ill or die if the stress continues [hormones
becoming depleted]
Modern Theories
Both Cannon and Seyle argued that there are general responses to stress, but it is now widely
recognized that there are individual differences in stress reactions.
From a psychosocial perspective, studies investigating the effect of stress on sympathetic arousal,
including heart rate, respiratory rate, and galvanic skin response (a measure of the degree to which the
electrical conductance of the skin is affected by sweating) consistently found individual differences in
the patterning of sympathetic arousal.
In addition, it is now recognized that activation of the HPA axis is an attempt to buffer the rather
damaging influence of prolonged SNS activation.
SNS activates immune system responses, encouraging inflammation; HPA activation suppresses the
immune/inflammatory response
In addition, we now know that most, if not all, of the endocrine hormones are affected by stress,
increasing or decreasing in fairly complex temporal patterns.
In general, stress activates those hormones that increase metabolic functioning and suppresses those
involved in long-term growth and maintenance.
The recognition of broader endocrine responses to stress has led to an argument for a third stress
pathway, through oxytocin.
Oxytocin is a hormone that is very important in reproductive activities such as breast-feeding.
It may also mediate social relations, and evidence has been provided that it might underlie sex
differences in stress reactions.
2. Stress and the Development of Chronic Illness
Stress can results in heart disease
Risk factors: blood pressure, cholesterol, atherosclerotic, and arteriosclerotic process, and immune
functioning, tumor proliferation, suppress natural killer (NK) cells
Allostasis- fluctuation in physiological systems to meet external demands
Allostatic load- the physiological costs of chronic exposure to fluctuating or heightened neural or
neuroendocrine responses that result from repeated chronic environmental challenges
Positive Physiological Changes
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Document Summary

Three different major ways to describe stress: stress as a physiological state. Classic theories: cannon (1915) was the first physiologist to systematically describe the physiological effects of stress. Hypothalamus secrets corticotrophin-releasing hormone (cha) which activates the activity. Pituitary releases adrenocorticotropin hormone (acth) into blood stream. Acth stimulates the cortex of adrenal glands to release corticosteroids [glucocorticoids] www. notesolution. com. 1: hans selye expanded on cannon"s conceptions in two ways. Thus, they have a wide range of effects. In general, stress activates those hormones that increase metabolic functioning and suppresses those. In addition, we now know that most, if not all, of the endocrine hormones are affected by stress, Stressful life events: there is some overlap between life events and individual trauma, uncontrollable stressors generally have more adverse impacts than those perceived to be under an individuals control. In general, the impact of stressful life events tends to diminish after 6-18 months.

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