The Journey Of Adulthood, 5/e Helen L. Bee & Barbara R. Bjorklund Chapter 3 Physical Changes The Journey of Adulthood 5/e by Bee & Bjorklund. Copyright

The Journey Of Adulthood, 5/eHelen L. Bee & Barbara R. Bjorklund

Chapter 3 Physical Changes

The Journey of Adulthood 5/e by Bee & Bjorklund. Copyright © 2004 by Pearson Education. All rights reserved.

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.


Theories of Primary Aging

• No single theory can explain all of the changes that occur in primary aging.


Oxidative Stress DNA damage

Natural selection

Genetic limits

Dietary intake

• Free radicals:

• damage DNA.

• lipofuscin, build up in cells and is implicated in numerous diseases.

• are inhibited by antioxidants.


Oxidative Stress



DNA damage


• Cells ability to repair DNA alterations decreases with age.

• Research evaluating this theory has been mixed.


Natural selection


• Aging is programmed into our biology once we have reproduced.

• Genes that contribute to good health and survival are favored by natural selection through prime reproductive years, but not middle and late adulthood.

• Genes that contribute to infirmity and premature death in middle and late adulthood are not reduced by natural selection and are thus passed on to the next generation.

• Difficult theory to test empirically

• Accounts for 35% of variability in 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.

• Telemores (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.


Dietary intake


• Promising explanation of aging.

• Age-related differences in number of calories metabolized by the body.

• Dietary restriction shown to increase longevity in lab rats.


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.


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.


Appearance

Physical changes over adulthood

Senses Musculoskeletal System

Cardiovascular and Respiratory Systems

Nervous System

Immune System

Endocrinological System


•Age-related changes height, weight, skin elasticity, and hair color and loss.

Appearance



Vision

Hearing

Smell and Taste

Senses



Vision

Senses


• 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.

• 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.


Hearing

Senses


• Hearing loss in higher tones and shortening of the loudness scale.

• Prebycusis

• 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


Smell and Taste

Senses


• 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.


Muscles

Musculoskeletal System


Bones

Muscles



• Significant loss of muscle tissue leads to a reduction in physical strength.

• Strength training can prevent this loss.


Bones



• Bone marrow gradually disappears from the bones of the arms and legs and becomes concentrated in the bones of the trunk.


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.


Bones




• Osteoarthritis occurs more frequently in women, older and overweight people.

• 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.

Cardiovascular and Respiratory Systems



• 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.

Nervous 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.

Immune System



• The climacteric is the age-related loss of reproductive ability.

Endocrinological System


In men:

1. Gradual decline in testosterone

2. Decrease in viable sperm, muscle mass, sexual desire, etc.

3. Decline in sexual response.

4. Erectile dysfunction is associated with age and can be treated with medication.

In women:

1. Menopause occurs signaling an end to reproductive abilities.

2. Ovarian failure related to drop in estrogen and changes in progesterone

3. Average age of menopause is 51.

4. HRT is commonly used with menopausal and postmenopausal women.


Slowing down

Effects of aging on behavior.


Stamina, Dexterity and Balance Sleep

Sexual Activity


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.



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 climacteric is the age-related loss of reproductive ability.

• Frequency of sexual activity drops from the 20’s into late adulthood.

• This research is limited by reliance on surveys.

• Factors that affect probability that an older person will have sexual relations:

Sexual Activity



1) physical ability

2) desire

3) availability of willing partner

4) access to physical and social space

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.

Recurring and unanswered questions


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The Journey Of Adulthood, 5/e Helen L. Bee & Barbara R. Bjorklund Chapter 3 Physical Changes The Journey of Adulthood 5/e by Bee & Bjorklund. Copyright