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This section of the skin is the outermost part and contains no arteries, veins or capillaries but is fed from the dermis via lymph.
The epidermis can be divided into three distinct layers with the basal layer being the bottom most layer of this thin epidermis.
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The basal layer is also known as the Stratum germinativum, since this is where "birth" is given to new cells.
There is a constant generation of new cells, with the younger cells found at the deepest part, and the oldest on top.
The basal layer not only contain basal cells, but also hosts the class of cells referred to as melanocytes - the cells that produce the melanin in your skin, which gives your skin its unique color.
Every 6th cell in the basal layer is normally a melanocyte cell. Racial difference influences the amount of melanocytes in the basal layer, as well as the arrangement of such cells.
When sunlight strikes the melanocytes it stimulates the production of melanin - which is in fact a defense mechanism of the body to prevent the harmful rays of the sun from entering the body. For more information regarding the dangers of sunlight radiation, please click here.
The next layer in the epidermis is the Stratum spinosum - also called the prickle cell layer - which is the thickest part of the epidermis, and derives it name from the spiny, prickly looking projections that link the cells in this layer. The cells within this layer are referred to as squamous cells, which are matured basal cells migrating up in the epidermis towards the outer surface.
These cells undergo modification when pushed to the surface and eventually contain no nucleus, are flattened and are charged with keratin - the same material which makes up human nails and hair.
These cells are not just old and charged with keratin, but are in actual fact dead cells, which eventually detach themselves and shed. These cells are arranged in an overlapping fashion and are the first line of defense against any substance trying to enter the body.
This top layer of dead cells is called the horny layer or Stratum corneum, which is somewhat acid in nature, and is also referred to as the acid mantle and is of use in protecting the skin from outside problems.
Dead cells are normally shed in a two weekly cycle, and an abnormal accumulation of these dead cells can result in flakiness and an ashen look, which is very noticeable in darker skinned people since it gives the skin a gray look.
In fair colored people, this abnormal build-up of dead cells results in a skin looking less-than-vital or healthy.
It is for this reason why exfoliation is recommended in skin care, since it helps to remove the dead cells from the skin surface.
Other pages dealing with the skin
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