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Skin is made up of three layers—the epidermis, dermis, and hypodermis— and acts as a protective barrier between internal structures and the outside world.

The epidermis is the outermost layer and is mostly made of keratinocytes to form the skin’s protective barrier. The epidermis also contains melanocytes which control skin color and protects other skin cells from DNA damage by absorbing UV rays.

The dermis is the skin’s thickest layer. It provides support and contains nerve endings, sweat glands, oil glands, hair follicles, blood vessels, and lymph vessels.

The hypodermis (also called the subcutaneous layer) is a layer of fat and connective tissue below the dermis.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Revised: December 13, 2022

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