AIMatMelanoma.org
en gb fr de es it iw el nl da fi sv no pl ru cs

Layers of the Skin

The First Layer: Epidermis

The thin top layer of skin we can see with the naked eye.

A waterproof barrier that protects us from bacteria and other microscopic organisms in the environment.

 

Cells within the epidermis:

 

  • Keratinocytes are specialized skin cells that make up most of the epidermis. The outermost part of the epidermis is made up of keratinocytes that have lost their nucleus, are full of a protein called keratin that makes them hard, and link together to form a waterproof barrier. Keratinocytes are constantly shed and replaced by squamous cells that turn into keratinocytes as they migrate up to the top of the skin.

  • Squamous cells are live keratinocytes that make keratin, an important skin protein.

  • Basal cells make up most of the basal layer, the innermost layer of the epidermis. They are the only cells in the epidermis that divide and create new cells called keratinocytes.

  • Melanocytes are located in the basal layer of the epidermis. They are interspersed regularly between the basal cells. Melanocytes produce melanin, a pigmented protein that gives us our skin and hair color and provides protection against the damaging effects of ultraviolet radiation.

 

For more on melanocytes click here.

 

The Second Layer: Dermis

The thicker, second layer of skin located beneath the epidermis.

Contains blood and lymph vessels, nerve endings, muscle fibers, oil and sweat glands, and hair follicles

 

There are 2 layers within the Dermis:

 

  • Papillary dermis, the upper layer

    • Made of loose connective tissue, blood vessels, and nerves. Fingerlike projections called papillae connect the dermis to the epidermis and provide the epidermis with vital nutrients.

  • Reticular dermis, the thicker lower layer

    • A network of collagen fibers, dense connective tissue that gives skin its elasticity and strength

    • Contains a rich supply of blood vessels and nerves, as well as lymph vessels, glands, and hair follicles

 

The Bottom Layer: Subcutaneous Layer, or Subcutis

A thick layer of fat and connective tissue beneath the dermis

 

  • Like the dermis, it contains a rich supply of blood and lymph vessels.

  • It insulates and saves your body heat, acts as a shock absorber to protect your underlying tissues and organs from injury, and is a source of reserve energy.