2. Objectives
This presentation will describe aging from both a
biological/physiological and a psychosocial
perspective.
Biological/physiological theories will be presented in
two main categories, program theories and error
theories.
Psychosocial theories will be discussed in two main
categories, full-life theories and mature-life theories.
7. What is Aging?
The gradual and spontaneous changes that
occur in maturation from infant to young adult.
These changes create a normal physiologic
decline seen in middle and late adulthood.
Changes during puberty
Graying of hair
8. Senescence
The process by which a cell looses its ability to
divide, grow, and function. This loss of function
ultimately ends in death.
A degenerative process, only.
Has no positive features.
9. Normal vs. Healthy Aging
Normal Aging
Diseases & impairments
of elderly
People age differently
Diabetes may be a
common disease of
adulthood, but is not
experienced by all aging
adults.
Healthy Aging
Minimize and preserve
function
Influenced by lifestyle
choices
One may have a healthy
life until senescence
makes life impossible.
10. Life Expectancy
Some Factors Influencing Your Life Expectancy
Heredity
Disease Processes
Medical Treatment
Lifestyle Choices
Nutrition
11. Theories of Aging
“The link between genes and
lifespan is unquestioned. The
simple observation that some
species live longer than others --
humans longer than dogs,
tortoises longer than mice -- is one
convincing piece of evidence.”
The National Institute on Aging
12. Theories of Aging
All aging begins with genetics
Aging changes the biochemical and
physiological processes in the body
Cell and molecular biologists examine and
propose theories to explain the aging process
– What causes aging?
– How can you influence aging …prolong life?
13. The Two Main Aging Theory Categories
Programmed Theories
Aging has a biological timetable or internal biological
clock.
Error Theories
Aging is a result of internal or external assaults that
damage cells or organs so they can no longer function
properly.
Many theories are a combination of programmed and
error theories.
14. Programmed vs. Error Theories
Programmed Theories
Programmed
Senescence Theory
Endocrine Theory
Immunology Theory
Error Theories
Wear and Tear Theory
Rate-of-Living Theory
Cross-linking Theory
Free Radical Theory
Error CatastropheTheory
Somatic Mutation Theory
16. Programmed Senescence Theory
The result of sequential switching “off” or “on” of
specific genes.
Example – “Hayflick’s Limits”
– Fibroblasts removed from umbilical cord & cultured
– Fibroblasts divide and repeated until ~ 50 divisions
– Will not divide past this point
17. Telomeric Theory
This is an extension of the “Hayflick Limit.”
Telomeres are specialized DNA sequences at the end of
chromosomes.
– They shorten with each cell division.
– When the telomeres become too short, the cell enters the
senescence stage.
In the normal process of DNA replication, the end of the
chromosome is not copied exactly, which leaves an
unreplicated gap.
18.
19. Telomeric Theory
The enzyme, telomerase, fills the gap by
attaching bases to the end of the chromosomes.
As long as the cells have enough telomerase to
do the job, they keep the telomeres long enough
to prevent any important information from being
lost as they go through each replication.
– With time, telomerase levels decrease.
– With decreasing telomerase levels, the telomeres
become shorter and shorter.
22. Telomeric Theory and Cancer
90% of cancer cells have been found to possess
telomerase.
– Telomerase prevents the telomere from shortening.
– This allows the cancer cells to reproduce, resulting in tumor
growth.
Research areas
– Measuring telomerase may help detect cancer.
– Stopping telomerase may fight cancer by causing death of
cancer cells.
– Telomerase may be used to help with wound healing or the
immune response.
23. Endocrine Theory
Biological clocks act through hormones to
control the pace of aging. Hormones effects
growth, metabolism, temperature, inflammation
and stress.
Examples- Menopause
– Decreased level of estrogen & progesterone
– Hot flashes, insomnia
24. Immunologic Theory
A programmed decline in the immune system
leads to an increased vulnerability to disease,
aging and death
Example- Decreased T cells (helper cells) in
adults
– Increased diseases in older adults
– Increased autoimmune diseases in adults
25. Error Theories
Wear and Tear Theory Error Free Radical Theory
Rate-of-Living Theory CatastropheTheory
Cross-linking Theory Somatic Mutation Theory
26. Wear and Tear Theory
Years of damage to cells, tissues and organs
eventually wears them out, killing both them and
the body
Example- Wearing out of the skeletal system
such as in osteoarthritis
Wear and tear can be viewed as a result of aging
and not the cause of it.
27. Rate-of-Living Theory
The greater an organism’s basal metabolic rate, the
shorter the life span.
Free radicals or other metabolic by-products play a
role in senesce.
Example
Animals with the most rapid metabolisms tend to
have the shortest lifespans, i.e, birds have a shorter
lifespan than humans.
Studies examining the relationship between
metabolic rates and longevity have produced
inconsistent results, limiting the usefulness of this
theory.
28. Cross-Linking Theory
The accumulation of cross-linked proteins
damages cells and tissue, slowing down bodily
processes.
Example
Non-enzymatic glycosylation reactions occur
when glucose molecules attach to proteins
causing a chain of chemical reactions resulting
in a structural change to the proteins.
– Loss of flexibility of connective tissue
– Microvascular changes in arteries
29. Free Radical Theory
During aging, damage produced by free radicals cause
cells and organs to stop functioning.
A free radical is a molecule with an unpaired, highly
reactive electron. One type of very reactive free radical
is the oxygen free radical, which may be produced
during metabolism or as a result of environmental
pollution.
Oxygen free radicals are formed in your cells, naturally,
during the oxidation of food to water and carbon dioxide.
30.
31. Free Radical Theory
The free radical “grabs” a electron from any
molecule it its vicinity.
It does this because electrons like to exist in
pairs.
When it “grabs” an electron from another
molecule, it damages the other molecule.
32. Free Radical Theory
Some of the molecules that may be damaged by free
radicals are fats, proteins, and DNA (both in the nucleus and
in mitochondria).
If membrane fats are attacked, then you get the breakdown
of the cell membrane. If it is a red blood cell membrane,
you get hemolysis.
If proteins are attacked, you get the breakdown of proteins,
which may result in the loss of biological function and the
accumulation of “catastrophic” compounds.
If DNA is attacked, you will get a mutation that may cause
aging or cancer.
33. Free Radicals
As the free radical (green) attacks the membrane it
can release another type free radical (blue).
34. Damaged membrane
The free radical (blue) attacks the DNA releasing another
free radical (purple).
mitochondrion
35. Free Radical Theory
Free radicals do not go unchecked. The body has a
multi-layed defense system that reacts and detoxifies
the damaging radicals.
Defenses include:
– Natural antioxidants in the body, such as bilirubin.
– Enzymes such as superoxide dismutase (SOD), catalase, &
glutathione peroxidase.
– Dietary antioxidants such as beta carotene, and the vitamins
C and E.
36. Free Radical Theory
Under normal conditions, your natural defense
mechanisms prevent most of the oxidative
damage from occurring.
The free radical theory of aging proposes that,
little-by-little, small amounts of damage
accumulate and contribute to deterioration of
tissues and organs.
38. Free Radical Theory
For example, when Vitamin E “scavenges” free radicals,
it becomes a free radical and may be more carcinogenic
than the original free radical.
This is the reason why taking high doses of vitamin E
SUPPLEMENTS appears to INCREASE cancer risk in
a person, not decrease cancer risk.
39. Free Radical Theory
Not all free radicals cause damage.
You use free radicals as part of your immunological
response system.
– Macrophages engulf bacteria
– Free radical reactions produced inside the macrophage
oxidize and kill bacteria.
Question: Does it make any biological sense to try
to eliminate all free radicals in your body by taking
supplements?
41. Can you delay or stop aging by taking
vitamins and other free radical scavengers?
There is no evidence-based proof that dietary
supplements delay or stop aging. This is a big area of
nutrition quackery. BEWARE!
Remember, there is a lot of evidence-based proof that
taking some supplements INCREASES cancer rate, for
example lung cancer. Smokers who take beta-carotene
supplements have higher lung cancer rates than
smokers not taking these supplements.
Therefore, the risk/benefit ratio is in favor of NOT taking
SUPPLEMENTS to retard aging.
42. Catastrophe Theory
Any damage to the enzyme systems that
synthesize proteins in the body results in faulty
protein synthesis.
The faulty proteins continue to accumulate in the
cell until they reach a level that damages the
cells, tissues, and organ
When enough damage accumulates, this may
result in cell malfunctioning ( aging) leading to
death.
43. Somatic Mutation
Genetic mutations occur and accumulate with age in the
somatic cell causing the cell to:
– Deteriorate
– Malfunction
Accumulation of mutations result in :
– Damage to the DNA
The theory states that aging is an imbalance between
DNA’s ability to repair itself and accumulating DNA
damage.
– When the damage exceeds the repair, the cell malfunctions
and this can lead to senesence.
45. Psychological Theories of Aging
1. Full-Life Development Theories (Erikson’s
Theory will be the only one discussed.)
2. Mature-Life Theories
1. Robert Peck’s Theory
2. The Activity Theory (Neugarten’s Theory will be the
only one discussed.)
3. The General Theory of Disengagement
46. Full-Life Development Theory
Eric Erickson was one of the first psychological
theorists to develop a personality theory that
extends to old age.
47. Full-Life Development Theory
Major Concepts
The ego is a positive driving force for
development.
– The ego’s job is to establish and maintain identity.
– A lack of identify leads to lack of direction and non-
productivity.
There are stages of personality and ego
development.
48. Full-Life Development Theory
Major Concepts
The last stages are “Adulthood” & “Late Life Stage.”
“Adulthood” is characterized by a struggle between
“Generativitiy” and Stagnation.
“Generativity”
– Giving back to society by raising children
– Being productive at work
– Being involved in the community
– Guiding, parenting, and monitoring the next generation
49. Full-Life Development Theory
Major Concepts
Stagnation
– Being unproductive
– Feeling anger, hurt and self absorption
As one becomes mature, there is a struggle between
“Ego Integrity” & despair
“Ego Integrity”
– Exploring life as a retired person who is not identified with an
occupation
– Contemplating accomplishment
– Feeling life is successful
50. Full-Life Development Theory
Despair
– Feeling guilt about the past
– Not accomplishing life goals
– The final pathway:
dissatisfied despair
depression hopelessness
52. Mature-Life Theories
Robert Peck
The elderly go through three developmental
stages to reach full psychosocial development.
Stage 1 - Ego Differentiation vs. Work Role
Preoccupation
Stage 2 - Body Transcendance vs. Body Preoccupation
Stage 3 - Ego Transcendance vs. Ego Preoccupation
53. Stage 1
Ego Differentiation vs. Work Role Preoccupation
As a person matures, that person moves from
“Work Role Preoccupation” which is a concept
that describes defining oneself through work or
an occupation.
A person finds new meaning and value in his or
her life. This process is called “Ego
Differentiation.”
54. Stage 2
Body Transcendance vs. Body Pre-occupation
A person either accepts the limitations that
accompanies the aging process (Body
Transcendance) or dwells on diminishing abilities
(Body Pre-occupation).
55. Stage 3
Ego Transcendance vs. Ego Preoccupation
Self-examination occurs.
If a person believes his or her life has worth and “life
contributions” will live on after death, the person experiences
“Ego Transcendence.”
Otherwise, the person may feel that he or she has lived a
useless life and experience “Ego Preoccupation.”
56. Mature-Life Theories
Neugarten
Bernice Neugarten describes tasks that must be
accomplished for successful aging. Some of
these tasks include:
Accepting reality and the imminence of death.
Coping with physical illness.
Accepting the necessity of being dependent on
outside support while still making independent
choices that can give satisfaction.
58. Mature-Life Theories
General Theory of Disengagement
This theory is controversial and has these features:
Both older people and society mutually withdraw from
each other.
A person gradually disconnects from other people in
anticipation of death.
Intrinsic changes in personality occur which allow a
person to psychologically withdraw from society’s
expectations.
Note: This is the opposite of “Activity Theory.”
59. Summary
This presentation has described aging from both a
biological/physiological and a psychosocial
perspective.
Biological/physiological theories are divided into two
main categories, program theories and error
theories.
Psychosocial theories are divided into two main
categories, full life theories and mature life theories.
