Stratum lucidum

Stratum lucidum is a thin layer of the epidermis that is found in the skin of the palms and soles. It is part of the skin's barrier function and is only present in thick skin areas that experience a lot of friction.

Structure

The stratum lucidum is located between the stratum granulosum and the stratum corneum. It is composed of three to five layers of dead, flattened keratinocytes, which are filled with the protein keratin. These cells are transparent and have a glassy appearance, which is why the layer is named "lucidum", meaning "clear" in Latin.

Function

The main function of the stratum lucidum is to provide a barrier against bacteria and other harmful agents. The keratin in the cells of this layer helps to waterproof the skin and prevent water loss. It also provides a layer of protection against friction, which is why it is thicker in areas of the skin that experience a lot of friction, such as the palms and soles.

Clinical significance

Changes in the stratum lucidum can be a sign of certain skin conditions. For example, in psoriasis, the stratum lucidum is often absent. In ichthyosis, a group of skin disorders characterized by dry, scaly skin, the stratum lucidum can be thicker than normal.

See also

• Epidermis (skin)
• Keratin
• Stratum granulosum
• Stratum corneum

References

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  Diagram of the epidermal layers

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  Illustration of skin layers