The skin is the body's largest organ, and one of the most important. It has a
surface area of 15 to 20 square feet. It has been estimated that every square
centimeter of the skin contains about a half million cells that are constantly
dying and being replaced.
The skin protects us against getting dried out and prevents microorganisms
from penetrating our bodies and causing infections. It also prevents us from
getting poisoned by toxic materials in the environment. Equally important, the
skin regulates the body temperature by evaporating water.
The outer part of our skin is called the epidermis and consists of different
cell layers with an average thickness of 0.25 mm. The deepest layer of the
epidermis is the only living one.
The cells originating from this
deeper, basal layer undergo a differentiation process that transforms them into
a variety of protective substances. These substances migrate to the outermost
layers of the skin where they serve as barriers against dehydration, infection,
and poisoning. The most important of these substances are keratins and skin
lipids.
Because our skin is constantly losing parts of its surface due to friction
with clothing or abrasions, it has a constant need to regenerate. As the outer
layer is sloughed off layer by layer, it is being replaced from the underlying
cells.
The regeneration process culminates in the formation of the outer layer of
the skin, which consists of about 15-20 layers of horny cells (mainly keratins)
which are embedded in a matrix of skin lipids. As we age, the regeneration
process becomes less efficient and wrinkles and other signs of age appear.
Sun Damage Direct exposure to sunlight is recognized as
being highly destructive to the skin - even when the exposure does not result in
sunburn.
Sunburn does not injure the dead cells in the outer layer of your skin—it's
the living cells in the lower layers of the epidermis that become damaged. These
cells become inflamed and red due to the increased blood circulation your body
directs to the site of the injury to speed the healing process. If these cells
are destroyed, the skin's sensory cells become damaged and you'll feel pain. If
a large part of the skin cells are destroyed, you will become feverish and the
skin will blister. Other changes will be induced within the epidermis, such as
its thickening and increased amounts of melanin are produced, which darkens the
skin, resulting in a tan.
After a totally new basal layer of the epidermis has been built up, the
worthless sunburned skin will peel off. More important, the self-regenerating
potential of your skin is exhaustible, and after several sunburns, premature
aging of the skin occurs.
Sources: H.E. Junginger Ph.D., Head, Department
of Pharmaceutical Technology, University of Leiden, The Netherlands
Junginger Ph.D., Hans. The human skin: your
largest organ. Aruba Aloe Skin Care. May 30, 2001. Online [ http://www.arubaaloe.com/humanskin.htm]
Junginger Ph.D., Hans. The regeneration of the
human skin. Aruba Aloe Skin Care. May 30, 2001. Online [ http://www.arubaaloe.com/regener.htm]
The information provided herein is of a general nature and is in no way
intended to replace the knowledge, assistance or diagnosis of your
physician or healthcare provider. All decisions regarding your health are
your sole responsibility and that of your physician or healthcare
provider, as the case may be. For specific guidance regarding your
personal health, we strongly advise that you consult your physician or
healthcare provider. Schering-Plough Canada cannot be held responsible
for any interpretation or misinterpretation you may make of the
information provided herein.
