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Why Skin Ages?
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The dermis contains sebaceous (oil) glands, hair
follicles, blood vessels, nerves and sweat glands,
as well as connective tissue. Collagen fibers
provide structural integrity and support, and
elastic fibers provide elasticity, as the name
implies. The subcutaneous portion of the skin
includes blood vessels and a fat layer (adipose
tissue). Over time:
1. Sebaceous glands slow their oil production,
causing skin to be drier.
2. Collagen and elastin begin to be eroded and lose
their structural framework.
3. The fat layer below the dermis thins. |
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Chemical Changes: The process
of metabolism itself, while creating energy that
powers the cell, also creates damaging oxidizing
chemical intermediates, known as Reactive Oxygen
Species (ROS). The generation of ROS leads to
oxidative stress.
Extrinsic Aging occurs when the skin is exposed to
added, environmental factors, such as UV light
(sunlight or tanning bed), cigarette smoke, weather
conditions, chemicals in the workplace, and the
like.
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Free
Radicals - whether intrinsically or
extrinsically generated, as shown in
the figure above - are the primary
operatives in this skin sabotage,
and the most common type of ROS.
Free radicals are highly unstable
molecules that occur in all tissues
of the body, including the skin, and
all parts of the cell. They are
unstable because they have an
unpaired electron. Free radicals
must therefore attempt to pair with
electrons in other molecules in
order to become "complete" and
stable in terms of electron
configuration. This is why free
radicals “attack” other molecules,
resulting in cellular damage, DNA
damage, inflammation, and new
unstable molecules (more free
radicals)! Because new free radicals
are formed, they then go on the
attack again. That's why free
radicals are so dangerous: they
cause chain reactions. The chain
propagation of these radicals is
quenched, or terminated, by stable,
less reactive molecules, most
notably, antioxidants.
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