II- Causes of Skin Aging
a- Internal Genetic Causes
b-
External Causes
·
Stress
·
Pollution
·
Sun Exposure
·
Cigarettes & poor or bad nutrition
III- Physiological Aging of
skin cells
·
Skin cells become less receptive to stimulation by
hormones or other physiological agents.
·
Skin cells loose their capacity of stocking nutrients
and energy and of using oxygen.
·
Cellular metabolism (synthesis of nutrients &
elimination of toxins) declines.
·
Microcirculation weakens and thus there’s less available
new oxygen for cell oxygenation and renewal.
·
Cellular renewal slows down.
·
The cells loose part of their internal fluids
·
Less sebum is secreted the skin becomes dryer
·
Decrease of collagen & elastin synthesis and renewal.
·
A bad and rigid collagen is formed.
·
Breaking down of more elastin by enzyme elastase that
leads to skin flaccidity.
·
Cells adaptation to external variations decreases; skin
becomes more reactive and sensitive.
·
Immune response decreases also; skin becomes prone to
infection and inflammatory reactions.
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