Ever wonder how your skin works? Here's a quick lesson...

LAYERS OF THE SKIN

 The Epidermis
 
The Epidermis is made of 5 layers. Skin cells start in the lowest layer, and move through all layers until reaching the surface of your skin.

  • Stratum Germinativum: The lowest layer of cells; contains melanin
  • Stratum Spinosum: Here, cell appendages become desmosomes (the structures that assist in holding cells together)
  • Stratum Granulosum: Cells resemble granules- they are filled with keratin and produce intercellular lipids
  • Stratum Lucidum: A clear layer made of small cells that let light pass through. ONLY FOUND ON PALMS OF HANDS AND SOLES OF FEET!
  • Stratum Corneum: Outer most layer that skin therapists are primarily concerned with

Once a cell reaches your outer layer, it becomes dry and will eventually flake off, or be exfoliated off. The process of cells moving through your 5 layers is referred to as cell turnover, and the quicker it happens, the more youthful skin will appear. Chemical exfoliation can assist in speeding up this process. Typical cell turnover rates:

  • Teenagers…15-28 days
  • Midlife…28-42 days
  • 50 and older…can take up to 90 days

The pH of the stratum corneum is between 4.5 to 6.0 (slightly acidic). This pH maintains a healthy outer layer, allowing skin to protect us from environmental exposure, bacteria, etc. This is why we want to use products (especially exfoliants) with a pH no lower than 3.5, and cleansers that are not too alkaline. When our skin is not in its’ normal pH range, it can feel dry, itchy and tight.


The Dermis

This is the layer of connective tissues below the Epidermis, and is about 25 times thicker than Edipermis. It contains:

  • blood and lymph vessels to nourish the skin
  • oil and sweat glands
  • nerves
  • arrector pili muscles (which cause goose bumps!)

The Dermis is made of 2 layers:

  • Papillary Layer: Papillae (cone-shaped structures at the bottom of hair follicles) are located here. Attached to papillae are either: looped capillaries to nourish epidermis, or tactile corpuscles (nerve endings to sense touch and pressure)
  • Reticular Layer: Deepest layer of dermis. About 70% of this layer is collagen. Elastin also lies here, but is only about 1/15 of the collagen amount.Hyaluronic Acid is found in between the fibers of this layer.


INTERESTING SKIN FACTS

  • Skin is the heaviest organ in the body, and makes up about 15% of total body weight
  • Each inch of skin contains approximately:
    o 15 feet of blood vessels
    o 65 hairs
    o 650 sweat glands
    o 12 feet of nerves
    o 1,300 nerve endings
  • Skin keeps your body at the correct temperature
  • We lose about 30,000 to 40,000 dead skin cells every minute (which accounts for a large amount of dust we see!)

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