The epidermis is a tissue made up of several layers whose primary function is to protect the underlying components from the action of harmful external physical agents.
Thanks to the arrangement of the cells, in fact the epidermis is not easily permeable to aqueous substances and pathogenic agents, such as viruses and bacteria.
The epidermis is a tissue made up of 5 layers that from the innermost to the outside layer are called stratum basale, stratum spinosum, stratum granulosum, stratum lucidum and stratum corneum. In the stratum basale there are stem cells, cells with the potentially endless capacity to divide and reproduce.
When these rise to the surface, they degenerate (the so-called apoptosis or programmed death), keratinising to form an effective barrier.
Thus, the stem cells become converted into horny cells. |
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E |
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Human skin
cheratinized
pavement hepithelium |
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D |
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C |
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B |
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Layers from the underlying derma: |
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A |
A |
stratum basale |
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B |
stratum spinosum |
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C |
stratum granulosum |
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D |
stratum lucidum |
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E |
stratum corneum or scaling |
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