Everything about Epidermis Skin totally explained
Epidermis is the outermost layer of the
skin. It forms the waterproof, protective wrap over the body's surface and is made up of stratified squamous
epithelium with an underlying
basal lamina.
Components
The epidermis is avascular (contains no
blood vessels) and is nourished by
diffusion from the
dermis. The main type or the four principal types of cells which make up the epidermis are
keratinocytes,
melanocytes,
Langerhans cells and
Merkels cells.
The outermost layer of epidermis consists of 25 to 30 layers of dead cells.
The human skin is organised in distinct layers. Cells are born in the deep layers and migrate outward, flattening as they go, to form a protective barrier of dead cells at the surface (stratum corneum). The stratum corneum is a multi-layered brick and mortar like structure. It consists of lipid bilayers with alternating hydrophilic and hydrophobic areas. This is an efficient barrier against chemicals that are unsoluble in fat and against those which are unsoluble in water.
To overcome this barrier is a challenge for the development of transdermally delivered drugs (like nicotine patches, topically applied pain reliev).
Sublayers
Epidermis is divided into the following 5 sublayers or strata, listed from the superficial to deep:
It is the deepest layer of the skin specifically the epidermis. The anatomical structure of it's composed of a single row of cuboidal of columnar keratinocytes.
Mnemonics used for remembering the layers of the skin (using "stratum basale" instead of "stratum germinativum"):
"Corn Lovers Grow Several Bales" (from superficial to deep)
"Come Lets Get Some Beers" (from superficial to deep)
"Before Signing, Get Legal Counsel" (from deep to superficial)
"Californians Love Girls in String Bikinis" (from superficial to deep)
Additional images
Image:Skinlayers.png|Section of epidermis.
Image:Skinn_layer_drawing.jpg|Skin layers.
Image:Spongiotic dermatitis (2) Dyshidrotic .JPG|Histopathological image of dyshidrotic dermatitis, showing focal spongiotic change in the epidermis.
Image:HautAufbau.png|Schematics of internal human skin depicting its inner structure.
Image:Gray942.png|The distribution of the bloodvessels in the skin of the sole of the foot.
Image:Gray944.png|Cross section showing layers of epidermis.
Further Information
Get more info on 'Epidermis Skin'.
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