Sunday, January 6, 2013

Layers of Skin...

The two main layers of the skin are the the Epidermis and Dermis. As a Esthetician I only have the authority to work on the Epidermis which as five layers and a Dermatologist can work on the Dermis.  Keratin is what makes up most of the epidermis as well as melanocytes, immune cells and Merkel cells.

The top layer is Stratum Corneum which is also known as the "horny layer" which is appropriate because this is were touch is felt and responses are made to stimuli. Also, there is a cell turnover rate of 28 days which is when the skin sheds and known as desquamation. The health of this layer is determined by the fat in cell membranes known as phosolipids and essential fatty acids.

The next layer would be the Stratum Lucidum which is very unique because here fingerprints and footprints are formed. This layer is clear and light passes through the small cells. Also, the soles of the feet and palms of hands are thickest with this layer. 

Next is the Stratum granulosum is where cells become keratinized to replace the old cells at the top layers. Natural moisturizing factors absorb water, prevent water loss and hydrate the lipid layer surrounding cells.

Stratum Spinosum also known as the spiny layer that have desmosomes which are the protein bonds that create communication between the cells. This is the largest layer of the skin which makes sense because antigens are discovered and the Langerhans immune cells help destroy foreign invaders that are a threat to the health. Pigment granules are formed by the synergy of keratinocytes and melanocytes.

The closest layer to the Dermis is the Stratum 
Germinativum also known as the basal cell layer which is the foundation of cell division, sensory cells and melanocytes. Melanin is what determines the color of skin, eye, and hair color while also absorbing or blocking UV radiation. The two types of melanin are pheomelanin in more light-colored people and eumelanin is in dark-colored people. The enzyme that urges melanoctyes to produce more melanin is Tyrosinase

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