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How does the epidermis protect the body from infection and dryness?

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Learn how regenerative properties of the skin helps to protect the human body from the external environment — human skin Human skin, whose cells are generated continuously by the body, serves as a protective barrier between the inside of the human body and the environment.

The epidermis protects the body from infection and dehydration through a combination of physical barriers and active immune responses.

Protection Against Dryness

The primary barrier against water loss is located in the lower portion of the stratum corneum. In this region, the spaces between compacted, keratin-filled cells are packed with lipid (waxy) lamellae. These lipid bilayers effectively block the outflow of water into the environment, maintaining internal hydration and structural integrity.123

Protection Against Infection

The epidermis serves as a multifaceted defense system against pathogens:
* Mechanical Barrier: The stratum corneum consists of tough, keratin-rich cells that provide a physical shield against toxins and microorganisms.24
* Chemical Defense: Skin glands secrete substances such as fatty acids and lysozyme, an enzyme that can break down the cell walls of certain bacteria.4
* Immunological Surveillance: Langerhans cells act as "sentinel" cells that recognize foreign molecules and initiate immune responses. Additionally, keratinocytes secrete epidermal cytokines, which enhance the body's ability to respond to infections and injuries.5