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Chapter 10

Chapter 10 Book Notes


Department
Health Studies
Course Code
HLTC22H3
Professor
Ingrid L.Stefanovic
Chapter
10

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Health, Illness, and Optimal Aging- Biological and Psychological Perspectives
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:
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
oOriginates in the spinal column (preganglionic nerves) and radiate to the target
organs (postganglionic nerves)
oPreganglionic are cholinergic they secrete the neurontransmitter aceteylcholine
oPostganglionic nerves use norepinephrine
oSympathetic nerves works on the: the heart, bronchi, gut, kidney, blood vessels,
sweat glands and piloerector muscles
oIn sympathetic/adrenal medulla (SAM)- nerves radiate to adrenal medulla- which
secretes epinephrine (adrenaline) and norepinephrine (noadrenaline) into blood
[stimulates organ muscles and blood vessels]
oEpinephrine- more powerful cardiac stimulant, increases metabolic rate
oNorepinephrine- stimulates the peripheral vascular system & raises blood
pressure
oSympathetic activation- increases heart rate, respiration rates, dilate pupils, diverts
blood flow & increases blood pressure [readies organism for physical activity]
oParasympathetic NS- brings the body back to homeostasis after stress or strenuous
physical activity
oProlonged increases in blood pressure and blood clotting would eventually result
in hypertension and cardiovascular disease
oHypothalamus secrets corticotrophin-releasing hormone (CHA)which activates
the posterior lobe of the pituitary
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Health, Illness, and Optimal Aging- Biological and Psychological Perspectives
oPituitary releases adrenocorticotropin hormone (ACTH) into blood stream
oACTH 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.
-Hans Selye expanded on Cannons 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 Cannons dualistic processes (SNS vs. PNS activation) by
describing three stages in reaction to stress.
oThe alarm stage is similar to Cannons 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.
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