Download The Effects of Aging On The Body

The Effects of Aging On The Body:
The Effects of Aging on Cells:
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Finite number of divisions (Hayflick limit)
Molecular damage by free radicals
Molecular (protein) damage by glucose
Accumulation of sugars, fats, proteins,
RNA
Decline in DNA
Mitochondria accumulate damage
Hydrolysis by rampant lysosomal
enzymes
Decline in cell number (30% by age 75)
The Effects of Aging on Skin:
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Collagen cross linkage
Age lines increase
Photoaging
Chronological aging
The Effects of Aging on the Nervous System:
1) Thousands of neurons lost per day after
age 30
2) 7% loss in brain mass by age 80
3) Cerebral cortex loses 45% of cells by age
80
4) Neurotransmitter production declines
5) Fewer cells + less transmitter = slower
6) Peripheral nervous functional loss results
in decrease sensitivity to pain, loss of
smell, taste, hearing balance
The Effects of Aging on the Cardiovascular
System:
1) Heart enlarges
2) Myocardium replaced by fat, collagen
3) Loss of reserve capacity at 1% per year
after age 30
4) Loss of elasticity of vessels results in
hypertension, inefficient control of local
flow
The Effects of Aging on the Respiratory
System:
1) Lungs lose elasticity
2) Respiratory membrane thickens
3) Breathing is more labored
The Effects of Aging on the Musculoskeletal
System:
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Osteocyte activity continues
Loss of bone mass in BOTH sexes
Osteoporosis common in women
Muscle mass declines
The Effects of Aging on the Digestive System:
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Loss of tone, slower peristalsis
Ca, B-12, Zn less well absorbed
Enzymes – OK
Gall bladder slows, stones develop
Liver metabolizes alcohol, drugs more
slowly
The Effects of Aging on the Immune System:
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Thymus gland involutes
T-cell number and function decline
B-cells identify antigen less efficiently
Increased incidence of autoimmunity
The Effects of Aging on the Reproductive
System:
1) Increased risk of certain fetal genetic
defects
2) Female - menopause
3) Male - significant decline in testosterone
and sperm after 65
4) Male benign prostatitis
5) Increased risk some cancers
The Effects of Aging on the Excretory System:
1) Decreased renal blood flow reduces
kidney function
2) Nephron number decreases
3) Less ability to concentrate urine
4) Bladder capacity declines
The Effects of Aging on the Endocrine System:
1) most glands continue to function normally.
Hayflick Limit:
1961 - Leonard Hayflick and Paul Moorhead
discovered that human cells derived from
embryonic tissues could only divide a finite
number of times in culture.
The Hayflick limit is the maximal number of cell
division that a cell can achieve in vitro.
When cells reach this limit they undergo
morphological and biochemical changes that
eventually lead to arrest of cell proliferation a
processes called cell senescence
Cell senescence is the phenomenon by which
normal diploid cells stop diving.