VJ

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VJ
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The Skin Though the Microscope
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• Most of us think of our skin in terms of How we
  look. A healthy skin not only looks well but
  performs vital body functions more efficiently.
  The skin is basically a wrapping which protects
  the encased organism.

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• As early as the 16th century, men such as
  Vesalius began to recognize the importance of
  certain parts of the human body the muscles,
  bones, the heart and lungs but they failed to
  recognize the skin as an organ which performs
  vital body fuctions.

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Even during the Italian Renaissance with its
great advances in science and the arts, there was
little knowledge of the skin. The great palaces
had no washing facilities at all.
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What is the color of the blood in the arteries?
Veins?
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• Facts about the skinThe skin is the bodys
  largest organ, covering the entire body. In
  addition to serving as a protective shield
  against heat, light, injury, and infection, the
  skin also
• regulates body temperature.
• stores water and fat.
• is a sensory organ.
• prevents water loss.
• prevents entry of bacteria.

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• Throughout the body, the skin's characteristics
  vary (i.e., thickness, color, texture). For
  instance, the head contains more hair follicles
  than anywhere else, while the soles of the feet
  contain none. In addition, the soles of the feet
  and the palms of the hands are much thicker.
• The skin is made up of the following layers, with
  each layer performing specific functions
• epidermis
• dermis
• subcutaneous fat layer
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• epidermisThe epidermis is the thin outer layer of
  the skin which consists of the following three
  parts
• stratum corneum (horny layer)This layer consists
  of fully mature keratinocytes which contain
  fibrous proteins (keratins). The outermost layer
  is continuously shed. The stratum corneum
  prevents the entry of most foreign substances as
  well as the loss of fluid from the body.
• keratinocytes (squamous cells)This layer, just
  beneath the stratum corneum, contains living
  keratinocytes (squamous cells), which mature and
  form the stratum corneum.
• basal layerThe basal layer is the deepest layer
  of the epidermis, containing basal cells. Basal
  cells continually divide, forming new
  keratinocytes, replacing the old ones that are
  shed from the skins surface.
• The epidermis also contains melanocytes, which
  are cells that produce melanin (skin pigment).
  Hair, scales, claws, hooves, fingernails, teeth
  are all part of the epidermis.

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• dermisThe dermis is the middle layer of the skin.
  The dermis contains the following
• blood vessels
• lymph vessels
• hair follicles
• sweat glands
• collagen bundles
• fibroblasts
• nerves
• The dermis is held together by a protein called
  collagen, made by fibroblasts. This layer also
  contains pain and touch receptors.The sebaceous
  glands are responsible for the excretion of the
  skin's natural oil (sebum). There are two types
  of sweat glands. The apocrine sweat glands fail
  to open directly onto the skin surface, but drain
  into large hair follicles. They are located near
  the armpits and around the genitalia, while the
  second type, the eccrine sweat glands, are
  distributed over the skins entire surface. The
  secretion of the apocrine differs to that of the
  eccrine it is thick and creamy in contrast to
  the watery solution of the eccrine glands. These
  glands aid in the removal of dirt and oil from
  the pores, help to regulate body temperature and
  also maintain the skin's PH balance.
• subcutisThe subcutis is the deepest layer of
  skin. The subcutis, consisting of a network of
  collagen and fat cells, helps conserve the bodys
  heat and protects the body from injury by acting
  as a "shock absorber."

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• The Ageing Process
• Aging is an inevitable fact of life. No matter
  how hard we attempt to avoid or eliminate it, the
  aging process continues to gnaw away at each and
  every one of us on a daily basis. However, this
  gradual but certain fact of reality need not be
  cursed upon. To appreciate the aging process you
  must firstly gain an understanding of how we as
  humans age. After all, the skin is the largest
  organ of the body therefore we must all endeavor
  to nourish and protect it.

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• Why Do We Age?
• Over the years wrinkles develop and we begin to
  notice our skin aging. These wrinkles are a
  result of damaged supporting tissue, the dermis.
  The dermis contains water, fat and cells, which
  aid in the production of two very important
  fibres, collagen and elastin. It is these
  fortifying fibres that give the skin firmness and
  elasticity. As we age, the dermis retains less
  water and fat - the skin ceases to look plump,
  fewer supporting fibres are produced - the skin
  is less resilient, oil flow slows considerably -
  the skin is drier, and tiny capillaries beneath
  the skin close off - the skin receives less
  oxygen and minimal nutrients. Cell renewal rate
  also slows, therefore the development of new
  cells takes longer, while old cells remain longer
  on the surface of the skin. The result of this
  rather simple process is, older looking skin
  showing visible creases, spots and sags.

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• Protecting Your Skin
• We all need to protect and look after our skin on
  a daily basis. There are many factors that
  influence aging and the awareness of these
  factors is essential if we are to avoid or at
  least monitor them. Stress, pollution, drugs,
  alcohol, cigarette smoking, improper nutrition,
  lack of sleep and ultra violet radiation play
  havoc on our lifestyle, which in turn stresses
  the skin tremendously and causes free radicals to
  attack the body. Free radical damage contributes
  greatly to the aging process by destroying
  healthy cells and damaging tissue. Free radicals
  are molecules of oxygen with unpaired electrons
  that desperately roam the body in search of
  normal healthy cells to latch onto. Once this
  attachment process takes place, oxidation begins
  - rather like metal rusting during weather
  exposure. Oxidation occurs most readily in fats,
  therefore cell membranes rich in fat, are prime
  targets.

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• Sun Exposure and Heat
• Sun exposed areas of the skin seem to show more
  wrinkles, spots, blemishes and pigment changes
  than covered areas. This aging and discoloration
  of the skin is believed to be caused by sun
  damage to the dermal connective tissue, resulting
  in the skins lose of elasticity and collagen.
  Dermal connective tissue that has been affected
  by ultra violet radiation (UVR) is not as firm or
  as resilient as normal connective tissue,
  therefore the surrounding blood vessels lack
  support. To protect your skin from the sun's
  harmful rays, slather sunscreen on all exposed
  areas whenever you step outside. Choose a
  sunscreen with a sun protection factor (SPF) of
  15 or higher, and one which blocks both UVA and
  UVB rays - a broad spectrum sunscreen. Ultra
  violet radiation can also penetrate and damage
  skin through clouds and glass, therefore remember
  to apply sunblock during winter and while
  driving. Sit in the shade whenever possible and
  avoid heat on the surface of the skin.

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• Smoking Drugs
• Smoking, drugs and alcohol encourage the invasion
  of free radicals, therefore these substances must
  be avoided whenever possible. Red wine consumed
  in moderation however, can be very beneficial to
  the skin due to a good supply of grape
  antioxidants. Smoking, on the other hand,
  deprives the skin of normal blood flow and also
  interferes in the healing process following
  cosmetic surgery on the skin. A smoker's face
  tends to show more lines and wrinkles than the
  face of a non-smoker the skin may appear
  slightly gray, have a leathery or rugged
  appearance or a subtle gauntness.