The outermost layer of the skin that forms the body’s primary protective barrier against the external environment.
It helps protect the body from physical injury, microorganisms, harmful chemicals, and ultraviolet (UV) radiation. It also helps reduce water loss and is continually renewed as older skin cells are shed and replaced by new ones.
The epidermis contains several types of cells, including:
- Keratinocytes, which produce keratin and make up most of the epidermis.
- Melanocytes, which produce the pigment melanin.
- Langerhans cells, which help the immune system detect foreign substances.
- Merkel cells, which contribute to the sense of touch.
The epidermis is organized into several layers of progressively maturing cells. Its outermost portion, the stratum corneum, consists mainly of dead, flattened keratin-filled cells that contribute substantially to the skin barrier.
QUICK FACT
The epidermis contains no blood vessels. It receives oxygen and nutrients from the underlying dermis.
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