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1/16/2012
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Primary and Secondary Aging
• Primary aging: aspects of physical changes with
age that are universally shared and inevitable, a result
of some basic biological process.
• Secondary aging: the part of the changes with age
in physical functioning that is not inevitable but may
result from widely shared environmental events.
• It is particularly difficult to separate the effects of
disease from normal aging.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Theories of Primary Aging
• No single theory can explain all of the changes
that occur in primary aging.
Oxidative Damage
Genetic limits
Caloric Restriction
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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1/16/2012
Theories of Primary Aging
Oxidative Damage
• Free radicals:
• damage DNA.
• cause lipofuscin, build up in cells that is
implicated as a cause of numerous diseases.
• are inhibited by antioxidants.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Theories of Primary Aging
Genetic limits
• Each species has a characteristic maximum life span.
• Correlation between the longevity of a species and the
number of times its cells will divide.
• Telomeres (lengths of repeating DNA at tips of cells)
appear to serve as timekeepers for the organism.
• Genetic limits may be integral part of normal
development for some cells.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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1/16/2012
Theories of Primary Aging
Caloric Restriction
• Promising explanation of aging.
• Age-related differences in number of calories
metabolized by the body.
• Dietary restriction shown to increase longevity in lab
rats.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Longevity, Life Expectancy, and Life Span
• Longevity: average expected length of life at any
particular time in history, in a particular culture; has
increased significantly in most of the world.
• Life expectancy: refers to the average number of years
a person of a given age can still expect to live; has risen
dramatically primarily through eradication of most
infectious diseases.
• Life span: refers to the upper boundary of years a
given species can expect to live. Despite increases in
longevity and life expectancy, life span has not shown
much change.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Longevity, Life Expectancy, and Life Span
• On average, women live longer than men do.
Some explanations:
1) Women are less likely to inherit sex-linked genetic
disorders.
2) Women are naturally protected from some diseases.
3) Women survive difficult conditions better.
4) Women are less likely to participate in high risk
behaviors.
5) Women are more likely to have safer jobs.
6) Women engage in more health oriented behaviors.
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Physical Changes over Adulthood
Outward Appearances
The Senses
Bones and Muscles
Cardiovascular and
Respiratory Systems
Brain and Nervous System
Immune System
Hormonal System
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Outward Appearances
• Age-related changes height, weight, skin elasticity,
and hair color and loss.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
The Senses
Vision
Hearing
Taste and Smell
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Physical Changes over Adulthood
The Senses
Vision
• Vision is the last sense to develop and
the first to show signs of aging.
• Lens thickens and yellows.
• Pupil loses ability to open in response
to reduced light.
• Lens also loses elasticity interfering
with its ability to accommodate.
• Loss of visual acuity (ability to perceive
detail in visual patterns).
• Presbyopia (reduced visual acuity) can
be corrected with glasses.
• Gradual loss of dark adaptation,
with marked decline after age 60.
• Cataracts involve the gradual
clouding of the lens of the eye, so
that images are no longer transmitted
sharply to the retina.
• Glaucoma is a dangerous buildup of
pressure inside the eye which can
destroy the optic nerve and lead to
blindness.
• No gender differences in visual
declines.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Physical Changes over Adulthood
The Senses
Hearing
• Hearing loss in higher tones and shortening of the
loudness scale.
• Presbycusis
• By age 65, ¼ of adults have some significant
hearing impairment, and rates rise sharply with age.
• Men more likely than women to suffer from
hearing loss
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
The Senses
Taste and Smell
• Four basic flavors (salty, bitter, sweet, and sour).
• Slight decline for salty and bitter, but nor for sweet and sour.
• Saliva production decreases and this affects taste.
• Changes in smell are more dramatic.
• Olfactory ability peaks between ages 20 and 40.
• Sense of smell drops slightly between ages 40 and
70 and then dramatically after age 70.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Bones and Muscles
Muscles
• Significant loss of muscle tissue leads to a
reduction in physical strength.
• Strength training can prevent this loss.
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Physical Changes over Adulthood
Bones and Muscles
Bones
• Bone marrow gradually disappears from the
bones of the arms and legs and becomes
concentrated in the bones of the trunk.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Bones and Muscles
Bones
• Calcium is lost from the bones, bone mass is
reduced and bones are more brittle and porous.
• Process begins around age 30.
• More pronounced in women than
men.
• Osteopenia is moderate bone
loss.
• Osteoporosis is severe bone loss
(20% of women over 50, 50%
over 80).
• Hormone Replacement Therapy
(HRT) can prevent the acceleration of
bone loss and increases bone mass
density.
• Calcium and Vitamin D are also
important for maintaining strong bones.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Bones and Muscles
Bones
• Osteoarthritis occurs more frequently in women,
older and overweight people.
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Physical Changes over Adulthood
Cardiovascular and Respiratory Systems
• Maximum oxygen uptake reflects the body’s ability
to take in and utilize oxygen during exercise. It
peaks in adolescence and declines steadily with age.
Varies significantly depending on activity level.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Physical Changes over Adulthood
Brain and Nervous System
• Loss of brain cells (neurons) in primary aging is
less than previously believed.
• Loss of total number of neurons but not all loss
translates to functional decline.
• Life-long plasticity (new dendrites and pruning).
• Slowing of transmission across the synapses
between neurons.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Immune System
• B cells make antibodies which react to infectious agents.
• T cells reject and consume harmful foreign cells.
• B cells show abnormalities with age, accounts for
increase of autoimmune disorders.
• With age T cells show reduced abilities to fight new
infection.
• Immune function is worsened by psychological stress
and depression.
• Nutritional supplements can enhance immune function.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Physical Changes over Adulthood
Hormonal System
• The climacteric is the age-related loss of
reproductive ability.
In men:
In women:
1.
Gradual decline in testosterone.
1.
2.
Decrease in viable sperm, muscle
mass, sexual desire, etc.
Menopause occurs signaling an
end to reproductive abilities.
2.
3.
Decline in sexual response.
Ovarian failure related to drop in
estrogen and changes in
progesterone.
4.
Erectile dysfunction is associated
with age and can be treated with
medication.
3.
Average age of menopause is 51.
4.
HRT is commonly used with
menopausal and postmenopausal
women.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Changes in Physical Behavior
Stamina, Dexterity and Balance
Sleep
Sexual Activity
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Changes in Physical Behavior
Stamina, Dexterity and Balance
• Stamina: ability to sustain moderate or strenuous
activity over a period of time. Declines due to
changes in the circulatory system and muscles.
• Dexterity: the ability to use the hands or body in a
skillful way, is lost as a result of arthritic changes in
the joints.
•Balance: the ability to adapt body position to change
also declines with age.
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Changes in Physical Behavior
Sleep
• Changes in the neurological system increase
likelihood of insomnia.
• Some sleep problems are due to health problems
and medications.
• Behavior changes can improve sleep (e.g., being
active).
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Changes in Physical Behavior
Sexual Activity
• The climacteric is the age-related loss of
reproductive ability.
• Frequency of sexual activity drops from the 20s
into late adulthood.
• This research is limited by reliance on surveys.
• Factors that affect probability that an older person
will have sexual relations:
1) Physical ability
3) Sexual partner
2) Desire
4) Privacy
5) Other forms of sensual activity
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
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Individual Differences in Primary Aging
• Genetics
• Lifestyle
• Psychosocial Factors
• Economics
The Journey of Adulthood 6/e by Bee & Bjorklund. Copyright © 2007 by Pearson Education. All rights reserved.
Recurring and Unanswered Questions
How quickly do we age?
How can we disentangle primary and secondary aging?
Why do individuals age at different rates and in different
ways?
• Specific experience may affect the rate, or
pattern, or physical aging (e.g., exercise).
• Heredity influences aging.
• Primary aging and economics.
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