Biology of Aging

Biologist & gerontologist used concept of senescence to explain biological aging
Senescence or normal aging refers to a gradual, time related to biological process that takes places as degenerative processes overtake regenerative or growth processes.

or
senescence: a change in the behavior of an organism with age leading to a decreased power of survival and adjustment

1. BIOLOGY OF AGING
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2. Biological Aging
•Biologist & gerontologist used concept of senescence
to explain biological aging
•Senescence or normal aging refers to a gradual, time
related to biological process that takes places as
degenerative processes overtake regenerative or
growth processes.
• or
senescence: a change in the behavior of an organism with age
leading to a decreased power of survival and adjustment
2

3. •Characteristics of senescence are as follows:
•The universal process
•The changes comes from organism itself
•The process occurred slowly
•The process contribute to deficit
3

4. •According to biological approaches, biological aging
can be divided into 3 types
•Primary aging
•Is the basic, shared, inevitable set of gains or declines
governed by some kind of maturational process
•Secondary aging
•Is the product of environmental influences, health
habits, or disease and is neither inevitable nor shared by
all adults
•Tertiary aging
•Refers to quickly deficit in the last few years prior to
death
4

5. Theories of Aging: Types
•Biologic
•Sociologic
•Psychologic
•Moral/Spiritual

6. Theories
6

7. Biologic Theories:
•Concerned with answering basic questions regarding the
physiological processes that occur in all living organisms as
they chronologically age

8. Foci of Biologic Theories
•Explanations of:
•1) deleterious effects leading to decreasing function of the
organism
•2) gradually occurring age-related changes that are progressive
over time
•3) intrinsic changes that can affect all member of a species
because of chronologic age

9. •ALSO:
•all organs in any one organism do not age at the same rate
•any single organ does not necessarily age at the same rate in
difference individuals of the same species

10. Biologic Theories: Divisions
•Stochastic:Explain aging as events that occur randomly and
accumulate over time
•Nonstochastic:View aging as certain predetermined, timed
phenomena

11. •Stochastic Theories or environmental theories
•Error Theory Free Radical Theory
•Cross-Linkage Theory
•Wear & Tear Theory

12. Error Theory
•Originally proposed in 1963
•Basis: 1)errors can occur in the transcription in any step of the
protein synthesis of DNA
•2) error causes the reproduction of an enzyme or protein that is
not an exact copy
•3) As transcription errors to occur, the end product would not
even resemble the original cell, thereby compromising its
functional ability

13. Error, cont’d
•More recently the theory has not been supported by research
•not all aged cells contain altered or misspecified proteins
•nor is aging automatically or necessarily accelerated if
misspecified proteins or enzymes are introduced into a cell

14. Free Radical Theory
•Free radicals are byproducts of metabolism--can increase as a
result of environmental pollutants
•When they accumulate, they damage cell membrane,
decreasing its efficiency
•The body produces antioxidants that scavenge the free
radicals

15. Free Rads, cont’d
•In animal studies, administration of antioxidants postpones
the appearance of diseases such as cardiovascular disease and
CA
•Free radicals are also implicated in the development of
plaques associated with Alzheimer’s

16. Cross-Linkage Theory
•Some proteins in the body become cross-linked, thereby not
allowing for normal metabolic activities
•Waste products accumulate
•Result: tissues do not function at optimal efficiency

17. C-L Theory, cont’d
•Some research supports a combination of exercise and dietary
restrictions in helping to inhibit the cross-linkage process

18. Wear & Tear Theory
•Proposed first in 1882
•Cells simply wear out over time because of continued use--
rather like a machine
•Would seem to be refuted by the fact that exercise in OA’s
actually makes them MORE functional, not less

19. •Nonstochastic Theories:
•Programmed Theory
•Immunity Theory

20. Programmed (Hayflick Limit)
Theory
•Based on lab experiments on fetal fibroblastic cells and their
reproductive capabilities in 1961
•Cells can only reproduce themselves a limited number of
times.
•Life expectancies are seen as preprogrammed within a
species-specific range

21. Immunity Theory
•Immunosenescence:Age-related functional diminution of the
immune system
•Lower rate of T-lymphocyte (“killer cells”) proliferation in
response to a stimulus
•& therefore a decrease in the body’s defense against foreign
pathogens

22. Immunity, cont’d
•Change include a decrease in humoral immune response,
often predisposing older adults to:
•1)decreased resistance to a tumor cell challenge and the
development of cancer
•2) decreased ability to initiate the immune process and mobilize
defenses in aggressively attaching pathogens
•3) increased susceptibility to auto-immune diseases

23. EMERGING THEORIES OF AGING
•Neuroendocrine Control (Pacemaker) Theory
•Metabolic Theory/Caloric Restriction
•DNA-Related Research

24. Neuroendocrine Control
•“…examines the interrelated role of the neurologic and
endocrine systems over the life-span of an individual”. (p. 24)
•there is a decline, or even cessation, in many of the
components of the neuroendocrine system over the lifespan

25. Neuro, cont’d
•Research has shown
•1) the female reproductive system is controlled by the
hypothalamus. What are the mechanisms that trigger changes?
•2) adrenal glands’ DHEA hormone
•3) melatonin (from pineal gland)--a regulator of biologic rhythms
and a powerful antioxidant. Declines sharply from just after
puberty

26. Metobolic Theory of Aging (Caloric
Restriction)
•“…proposes that all organisms have a finite amount of
metabolic lifetime and that organisms with a higher metabolic
rate have a shorter lifespan”. (p. 24)
•Rodent-based research has demonstrated that caloric
restriction increases the lifespan and delays the onset of age-
dependent diseases

27. DNA-Related Research
•Major Developments:
•Mapping the human genome (“…there may be as many as 200
genes responsible for contolling aging in humans”)
•Discovery of telomeres

28. SOCIOLOGIC THEORIES OF AGING
•Disengagement Theory
•Activity/Developmental Task Theory
•Continuity Theory
•Age Stratification Theory
•Person-Environment Fit Theory

29. •Changing FOCUS of Sociological considerations of aging:
•60’s focus on losses and adaptation to them
•70’s broader global, societal, and structural factors influencing
lives of OA’s
•80’s-90’s exploration of interrelationships between OA’s and their
physical, political, environmental & socioeconomic mileau

30. Disengagement Theory
•Cumming & Henry--1961
•Aging seen as a developmental task in and of itself, with its
own norms & appropriate patterns of behavior
•“appropriate” behavior patterns involved a mutual agreement
between OA’s and society on a reciprocal withdrawal.
•No longer supported

31. Activity Theory (Developmental
Task Theory)
•Havighurst, Neugarten, Tobin ~1963
•“Activity is viewed by this theory as necessary to maintain a
person’s life satisfaction and a positive self-concept”. (p.27)

32. Activity, cont’d
•Theory based on assumptions:
•1) it’s better to be active than inactive
•2) it is better to be happy than unhappy
•3) an older individual is the best judge of his or her own success
in achieving the first two assumptions

33. Continuity Theory
•How a person has been throughout life is how that person will
continuethrough the remainder of life
•Old age is nota separate phase of life, but rather a
continuation and thus an integral component

34. Age Stratification Theory
•Riley--1985
•Society consists of groups of cohortsthat age collectively
•The people & Roles in these cohorts change & influence each
other, as does society at large
•Thus, there is a high degree of interdependence between
older adults & society

35. Person-Environment Fit Theory
•Lawton, 1982
•Individuals have personal competencies that assist in dealing
with the environment:
•ego strength
•level of motor skills
•individual biologic health
•cognitive & sensory-perceptual capacities

36. P-E Fit, cont’d
•As a person ages, there may be changes in competencies &
these changes alter the ability to interrelate with the
environment
•Significant implications in a society that is characterized by
constantly changing technology

37. PSYCHOLOGIC THEORIES OF
AGING
•Maslow’s Hierarchy of Human Needs
•Jung’s Theory of Individualism
•Erikson’s Eight Stages of Life
•Peck’s Expansion of Erikson’s Theory
•Selective Optimization with Compensation

38. PROGRAMMED AGING RANDOM EVENTS
•Genetic life-span
theory
•Genetic
predisposition theory
•Telomere theory
•Specific system
theories
(Neuroendocrine
theory)
•Wear and tear theory
•Rate of living theory
•Waste product
accumulation theory
•Cross-linking theory
•Free radical theory
•Autoimmune theory
•Error theories
•Order to disorder
theory
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BIOLOGICAL THEORIES ON AGING

39. PROGRAMMED
AGING
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40. Programmed Ageing
•Aging and death are genetically determined and are
‘programmed’ in organisms
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Figure1:Thelifehistoryeventsofmammals,suchasdevelopment,reproduction,and
aging,typicallyoccurinproportiontotheentirelifespan.

41. Genetic Life-span Theory
•The length of life is genetically programmed.
•One example is the lifespan of organisms.
•An organism’s life span is part of its genetic makeup.
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42. 42

43. Telomere theory
•Telomere is the tail of chromosome
that is made of DNA but has no
genetic information.
•Telomeres protect the ends of
chromosomes from being degraded
and fusing with other chromosome
ends.
43

44. Telomere theory
•Telomere theory is based on the fact
that every time a cell replicate, it
loses part of its telomere.
•The older the cell (the more time it
has divided), the shorter the length
of telomeres.
44

45. •As the length of a telomere
decreases, changes may occur in
patterns of gene expression that
could affect both the functioning of
the cell and the organ system in
which it operates.
45

46. Neuroendocrine Theory
•Focus on changes in the hypothalamus and
pituitary gland that lead to decreased function
of the endocrine system and widespread
aging effects.
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47. 47

48. RANDOM
EVENTS
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49. BIOLOGICAL THEORIES OF AGING
•Wear and tear theory
•Suggest that the body is much like a machine
•The human body ages because it “wears out” over time in
response to the stresses of life
•Some kinds of exertion or activity promote vitality and are
essential to long life
•Other kinds of stressful activities are detrimental to
longevity
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50. 50

51. 51
BIOLOGICAL
CHANGES

52. Changes in Physical Appearance
•Hair
•Gradual thinning & graying of the hair
results from a cessation of pigment
production of both men & women
•Hair loss is cause by destruction of the
germ centers that produce hair follicles
•Men usually do not lose facial hair as they
age
•Women develop patches of hair on their
face especially on their chin
52

53. In women, especially near
menopause age as the
ovary functions slow
down then there can be
more DHEA or androgens
produced thus causing an
increase in facial hair or
hirsutism. As the woman
begins to produce more
androgens rather than
estrogens she may begin
to experience an increase
in facial hair.
53

54. •Skin integumentary system
•Wrinkles results from a complex process
•4 steps to make a wrinkle
•the outer layer of skin becomes thinner through
cell loss
•the collagen fibers that make up the connective
tissue lose much of their flexibility, making the
skin less able to regain its shape after a pinch
•elastin fibers in the middle layer of skin lose
their ability to keep the skin stretched out
•the underlying layer of fat, which helps provide
padding to smooth out the contours, diminishes.
54

55. •Body build
•2 noticeable changes occur in body
build during adulthood
•a decrease in height
•fluctuations in weight
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56. Body fluids
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57. •Changes in the Skeletal System
•The loss of bone
•Osteoporosis –defined as a decrease
in bone mass & strength
•Osteoarthritis –a degenerative joint
disease
57

58. •Changes in the Cardiovascular
System
•the main function of heart is
pumping blood
•Age-related structural changes
in the heart
•the accumulation of fat
deposit
•the stiffening of the heart
muscle due to tissue changes
58

59. •Cardiovascular diseases
•Ischemic heart disease
•Cardiac Arrhythmias
•Angina
•Myocardial infarction
•Atherosclerosis
•Cerebrovascular Disease
•Hypertension
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60. •Changes in the Respiratory System
•Age-related to structural and functional
•With increasing age, the rib cage and the
air passageways become stiffer
•Changes in the maximum amount of air
we can take into the lungs in a single
breath
•Respiratory disease
•Emphysema
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61. •Changes in the Immune system
•The immune system is a fascinating
array of cells and process
•lymphocytes
•antibodies
•autoimmunity
•Older adults’ immune systems take
longer to build up defense against
specific disease
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62. •Changes in the Reproductive System
•Women
•The major reproductive change in women during adulthood is the
loss of the ability to bear children
•Begins in the 40s, as menstrual cycles become irregular and by the
age of 50 to 55 it is usually complete -menopause
•A variety of physical and psychological symptoms
•Men
•Men do not have a physiological & cultural event to mark
reproductive changes.
•Do experience a normative decline in the quantity of sperm
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63. •Changes in the Sensory System
•Vision
•The major changes in visual
functioning can be group into 2
classes :
I. changes in the structures of the
eye
•disease: cataracts & glaucoma
II. changes in the retina
•usually begin 50s
•disease: macular degeneration &
diabetic retinopathy
63

64. •Age related decrease
in the ability to focus
on nearby objects -
presbyopia
•Age related decrease
the ability to see
detail and to
discriminate different
visual patterns -acuity
64

65. •Hearing
•Hearing loss with age is
greatest for high pitched
tones-presbycusis
•Tinnitus
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66. •Taste
•Taste ability changes
with age
66

67. •Smell
•The ability to detect odors
remains fairly intact until 60s,
when it begins to decline fairly
rapidly
•Touch
•Age-related changes in touch
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68. •Changes in Digestive System
•Intestine
•Liver
•Gall-bladder
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69. GALL BLADDER DISEASES
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70. •Brain
•Age related structural changes in the neuron
•Alzheimer’s disease
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