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How does the skin protect the body from microbes and harmful sunlight?

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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 skin serves as a vital protective barrier for the body through both mechanical and chemical defenses.

Protection Against Microbes

The skin acts as a primary mechanical barrier against infection due to its tough outer layer of cells, which are rich in keratin and constantly renewed. This intact surface prevents most pathogenic organisms from penetrating the body. Additionally, the skin provides chemical protection:1234
* Antimicrobial Secretions: Skin glands produce oily substances containing fatty acids that can kill certain bacteria.1
* Enzymatic Defense: Glands also secrete lysozyme, an enzyme capable of breaking down the outer walls of specific bacteria.1

Protection Against Harmful Sunlight

To defend against the damaging effects of ultraviolet (UV) radiation, the skin utilizes melanin, a chemical pigment. When skin cells are exposed to UV rays, melanin is activated and migrates toward the surface to absorb the radiation, thereby limiting its penetration into deeper tissues. This process, which results in a suntan, serves as a natural defense mechanism to help prevent further injury, such as DNA damage or carcinogenic changes.5