physical aging process

7/28/2019 Physical Aging Process

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PHYSICAL AGING

PROCESS

WHEN DOES OLD AGE BEGIN?


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DEFINITION OF AGING

Old and aging depends on the age

and experience of the speaker.

Chronological age - number of years

lived

Physiologic age - age by body

function

Functional age - ability to contribute

to society


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CHRONOLOGICAL

CATEGORIES

Young-Old - (ages 65 - 74)

Middle-Old - (ages 75 - 84)

Old-Old - (age 85 and older)


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FRAIL ELDERLY

Characteristics:

Poor mental and physical

health

Low socioeconomic status

Predominantly female

Possibly isolated living

conditions

More and longer hospitalstays, and

More money spent on

health care and drugs


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PHYSICAL THEORIES

OF AGING

What causes the body to age?


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PROGRAM THEORY

Cells replicate a specific number of

times and then die. Happens again,and again in lab experiments.


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ERROR THEORY

The structure of DNA

is altered as people age

Due to alterations,

DNA not read correctly Results in transcription

and translation

malfunction

Results in aging/illness/

cancer directly, or

indirectly


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CELLULAR THEORY

Normal wear and tear causes cells

to function improperly


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FREE RADICAL THEORY

Lipids in cell

membranes are exposed

to radiation or free

radicals Cell membrane

ruptures and cell dies

In test tubes this

actually occurs


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NUTRITIONAL MODEL THEORY

If animal fed 50-60%

less than it eats on its

own - lives longer

Assumption: Lean

mass, as opposed to

adipose tissue results in

greater health


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COLLAGEN THEORY OF AGING

As we age, collagen in body ages

also. Causes hypertension andother organ malfunctions


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MUTATING AUTO-IMMUNE

THEORY

Cells have normal functions - secrete

normal proteins

As cells age - mutate and secretions

viewed as foreign by body

Solicits immune response

Shuts cell down

Cause biological errors and entire

organ malfunctions


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NEURO-AGING THEORY

All cells undergo

nervous system

degeneration

Results in changes in

hormonal release

Leads to decline in cell

function


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NONE OF THESE

THEORIES TOTALLY

ACCEPTED

Scientists hypothesize it might becombination of several or all


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PHYSIOLOGICAL AGING

OF THE HUMAN BODYBY SYSTEMS


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SKIN, HAIR, NAILS

Loss of subcutaneous fat

Thinning of skin

Decreased collagen

Nails brittle and flake

Mucous membranes drier

Less sweat glands

Temperature regulationdifficult

Hair pigment decreases

Hair thins


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EYES AND VISION

Eyelids baggy and wrinkled

Eyes deeper in sockets

Conjunctiva thinner and

yellow Quantity of tears decreases

Iris fades

Pupils smaller, let in less light

Night and depth vision less

Floaters can appear

Lens enlarges


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EYES AND VISION

CONT. Lens becomes less

transparent

Can actuallybecome clouded

Results incataracts


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EYES AND VISION

CONT.

Accommodation decreases

Results in presbyopia

Impaired color vision, also -

especially greens and blues

Because cones degenerate


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EYES AND VISION

CONT. Predisposed to glaucoma

Increased pressure in eye

Decreased absorption of

intraocular fluid

Can result in blindness


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EYES AND VISION

CONT.

Macular degeneration

becoming more frequent

This is the patch of retinawhere lens focuses light

Ultimately results in blindness

Reason for current increase in

this condition unknown


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EARS AND HEARING

LOSS Irreversible, sensorineural

loss with age

Men more affected than

women Called presbycusis

Loss occurs in higher range

of sound

By 60 years, most adults

have trouble hearing above

4000Hz

Normal speech 500-2000Hz


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RESPIRATORY SYSTEM

Lungs become more rigid

Pulmonary function

decreases

Number and size of alveolidecreases

Vital capacity declines

Reduction in respiratoryfluid

Bony changes in chest

cavity


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CARDIOVASCULAR

SYSTEM Heart smaller and less elastic

with age

By age 70 cardiac output

reduced 70%

Heart valves become

sclerotic

Heart muscle more irritable

More arrhythmias

Arteries more rigid

Veins dilate


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GASTROINTESTINAL

SYSTEM Reduced GI secretions

Reduced GI motility

Decreased weight of liver

Reduced regenerativecapacity of liver

Liver metabolizes less

efficiently


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RENAL SYSTEM After 40 renal function

decreases

By 90 lose 50% of function

Filtration and reabsorption

reduced

Size and number of nephrons

decrease

Bladder muscles weaken Less able to clear drugs from

system

Smaller kidneys and bladder


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REPRODUCTIVE

SYSTEMMale:

Reduced testosterone level

Testes atrophy and soften

Decrease in sperm production

Seminal fluid decreases and

more viscous

Erections take more time Refractory period after

ejaculation may lengthen to

days


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REPRODUCTIVE

SYSTEMFemale: Declining estrogen and

progesterone levels

Ovulation ceases Introitus constricts and

loses elasticity

Vagina atrophies -

shorter and drier

Uterus shrinks

Breasts pendulous and

lose elasticity


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NEUROLOGICAL

SYSTEM

Neurons of central and peripheral

nervous system degenerate

Nerve transmission slows

Hypothalamus less effective in

regulating body temperature

Reduced REM sleep, decreased deep

sleep

After 50% lose 1% of neurons each

year


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MUSCULOSCELETAL

SYSTEM Adipose tissue increases with

age

Lean body mass decreases

Bone mineral contentdiminished

Decrease in height from

narrow vertebral spaces

Less resilient connective tissue

Synovial fluid more viscous

May have exaggerated

curvature of spine


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IMMUNE SYSTEM Decline in immune function

Trouble differentiating

between self and non-self -

more auto-immune

problems Decreases antibody response

Fatty marrow replaced red

marrow

Vitamin B12 absorption

might decrease - decreased

hemoglobin and hematocrit


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physical aging process

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