Aging Results
Since research into aging is not guided by
any one universally accepted theory,
genetic, cellular, and physiological
studies have yielded several hypotheses.
Genetics The most popular
genetic theory, the Error Theory, assumes that aging
is the result of the
accumulation of random genetic damage, or from small errors
in the flow of
genetic information. The damage or errors would reduce or prevent
proper cell
function. Cellular The best known theory of aging in cellular
research is
called the Hayflick Effect, which is named after the American
microbiologist
Leonard Hayflick. He found that certain human cells could only
divide a
limited number of times before they die. This may suggest that aging
is
"programmed" into cells. This could also account for the differences
in
the life spans of different animal species, and the differences in the
life
spans between the sexes within the same species. Physiological These
theories
focus on organ systems and their interrelationships. One area
currently being
investigated is the immune system. As we age the immune
system gradually loses
its capacity to fight off infections and other
invaders. As a result, antibodies
are produced that cannot tell the
difference between "friendly" cells
and "enemy" cells. Most experts now
believe that aging represents many
phenomena working together (Miller and
Keane 97). PHYSICAL CHANGES The physical
changes that accompany aging are not
necessarily incapacitating, even though
they may be discomforting or
limiting. The body has less strength and endurance
as it ages. The rate of
energy production in the body cells is gradually lowered
so that people tire
more easily and are more sensitive to weather changes.
Sexual desire and
ability lower although they never entirely end for either sex.
The
capacity to bear children ends in women with menopause, which is the
time
when the ovaries stop functioning, causing the menstrual cycle to stop.
Men
retain their reproductive function into the late years. The use of
eyeglasses
may become necessary, even if they were not necessary earlier in
life. Old
people can hear low tones fairly well, but their ability to hear
high tones
decreases. The capacity of tissue and bone to repair itself is
slowed, as is
cellular growth and division. Bones become brittle and skin
loses its thickness
and elasticity, causing wrinkles. As brain cells die some
capacity for
memorization and learning is lost. Breathing becomes difficult
and hardening
arteries circulation to worsen and blood pressure to rise.
Joints lose their
mobility and deteriorate from constant wear and pressure.
Finally, the liver
filters toxins from the blood less efficiently (Microsoft
Encarta
"Aging"). These are not all of the changes to the body that
are
brought about by aging, but these are the major ones. There is hope in
modern
medicine, though. Through the use of new technologies and drugs some
of these
changes can be slowed or prevented. System Results of Aging
Contributing Factors
SKIN -loses thickness and elasticity (wrinkles
appear) -bruises more easily as
blood vessels near surface weakens -Process
accelerated by smoking, -excessive
exposure to sun. BRAIN/NERVOUS SYSTEM
-loses some capacity for memorization and
learning as cells die -becomes
slower to respond to stimuli (reflexes dull)
-Process accelerated by overuse
of alcohol and other drugs, repeated blows to
the head. SENSES -becomes less
sharp with the loss of nerve cells -Process
accelerated by smoking, -repeated
exposure to loud noise. LUNGS -becomes less
effective as elasticity decreases
-Process accelerated by smoking, -poor air
quality, insufficient exercise.
HEART -pumps less efficiently, making exercise
more difficult -Process
accelerated by overuse of alcohol and tobacco, poor
eating habits.
CIRCULATION -worsens and blood pressure rises, as arteries harden
-Process
accelerated by insufficient exercise, smoking, poor eating habits.
JOINTS
-lose mobility (knee, hip) and deteriorate from constant wear and
pressure
(disappearance of cartilage between vertebrae results in old age
"shrinking")
-Process accelerated by injury, obesity. MUSCLES -lose
bulk and strength
-Process accelerated by insufficient exercise, starvation.
LIVER -filters
toxins from blood less efficiently -Process accelerated by
alcohol abuse,
viral infection. Microsoft Encarta. "Aging." MENTAL
CHANGES Along with
the loss of the ability of memorization and learning due to
brain cells dying
(Microsoft Encarta "Aging"); elderly people can be
affected by Alzheimer's
Disease. This disease is a progressive degenerative
disease of the brain, now
considered to be a leading cause of dementia among the
old. It affects an
estimated 2.5 to 3 million people in the U.S. The incidence
of this disease
increases with advancing age, but there is no evidence that it
is caused by
the aging process. The average life expectancy of a person
with
Alzheimer's is five to ten years. Alzheimer's patients show nerve
cell loss in
the parts of the brain associated with cognitive functioning.
The disease also
includes the formation of abnormal proteins known as
neurofibillary tangles and
neurotic plaques. Alzheimer's is also identified
by defects in the brain's
neurotransmitters, chemicals that transmit nerve
impulses, particularly
acetylcholine, which has been linked with memory
function. Recent findings show
that a small percentage of Alzheimer's cases
may have been inherited, and there
has been a link between the disease and
high amounts of aluminum in the brain
(Microsoft Encarta "Alzheimer's
Disease"). Senile Dementia This form
of intellectual impairment is observed
in elderly people. Approximately 10
percent of all people over 65 years of
age have clinically important
intellectual impairment. Although 20 percent of
these cases are treatable, such
as toxic drug reactions, most cases are
Alzheimer's Disease. Senile Dementia
begins with failing attention and
memory, loss of mathematical ability,
irritability and loss of sense of
humor, and poor orientation in space and time
(Microsoft Encarta "Senile
Dementia"). CONCLUSIONS 1. There is no one
theory about why we age, but the
subject is currently being researched in
several areas. 2. The body goes
through many changes as it ages, some of which
can be slowed or prevented
through the use of modern medicine. 3. Alzheimer's
Disease is probably
the most prominent mental disorder in elderly people, but
research has found
what it does to the brain, so a cure may be in
the
future.
Bibliography
Microsoft Encarta. Computer Software.
"Alzheimer's Disease."
Microsoft, 1993. Computer Software. "Senile
Dementia." Microsoft,
1993. Miller, Benjamin F., M.D., and Claire
Brackman Keane, RN, BS, M.Ed.
Encyclopedia and Dictionary of Medicine and
Nursing. USA: W. B. Saunders, 1972.
Riley, Matilda White. "Aging."
Microsoft Encarta. Computer Software.
Microsoft, 1993.