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The skin and melanoma

Men and women discussing melanoma skin cancer

This page is about your skin and what melanoma is. There is information about

 

A quick guide to what's on this page

The skin and melanoma

Melanoma is a type of cancer of the skin. The skin is a body organ. We don't normally think of it as an organ because it is so big.

The skin is made up of two layers called the epidermis and the dermis. The epidermis is the outer layer and the dermis is underneath. Between the layers are cells called melanocytes. These are the cells that become cancerous in malignant melanoma. Their job is to make a pigment or colouring for the skin. The pigment helps to protect the body from the ultraviolet light of the sun, which can cause burns.

People who originally come from hotter climates with more sunshine tend to have naturally darker skins. They do not have more of the melanocyte cells than paler races. But their melanocytes are more active, making more pigment.

Exposing your skin to the sun makes the melanocytes make more pigment. The pigment is then transferred to the other skin cells to protect them against the sun's rays.

 

CR PDF Icon You can view and print the quick guides for all the pages in the About melanoma section.

 

 

The skin

Melanoma is a type of cancer of the skin. The skin is a body organ. We don't normally think of it as an organ because it is so big. The skin covers every part of the outside of the body. It does several jobs for us. It

  • Protects the inside of the body from damage
  • Helps to keep our body temperature more or less the same
  • Gets rid of some waste products through sweat

The skin is made up of two layers, the epidermis and the dermis.

Diagram showing the structure of the skin

The thickness of the epidermis and the dermis varies from about 2mm to 4mm. This depends on the part of the body the skin is covering. The skin on the back, for example, is quite thick, with an epidermis and dermis of about 4mm. The skin on the face is much thinner.

 

Melanocytes and what they do

Between the dermis and epidermis are cells called melanocytes. They make a pigment or colouring for the skin. The pigment helps to protect the body from the ultraviolet light of the sun. Ultraviolet light can cause burns. Melanocytes are the cells that become cancerous in malignant melanoma.

People who originally come from hotter climates with more sunshine tend to have naturally darker skins. They do not have more of the melanocyte cells than paler races. But their melanocytes are more active and make more of the pigment. In paler people, the pigment gives you a sun tan. Exposing your skin to the sun makes the melanocytes make more pigment. The pigment is then transferred to the other skin cells to protect them against the sun's rays.

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Updated: 15 January 2014