The skin

Your skin is made up of several different types of cells, including squamous cells, basal cells and melanocytes.

The skin has many purposes, including:

  • protecting the body from injury and infection
  • helping to control body temperature
  • helping to control fluid loss
  • getting rid of waste substances through the sweat glands.
  • protecting the body from the harmful effects of ultraviolet (UV) light.

The skin has two main layers. The outer layer is the epidermis and the layer underneath is the dermis.

The structure of the skin

The dermis contains nerve endings, blood vessels, and sweat glands.

The epidermis contains three types of cell. On the surface are flat cells, known as squamous cells. Under these are rounder cells called basal cells. In between the basal cells are cells called melanocytes.

Melanocytes are cells that make a pigment called melanin. Melanin gives our skin its natural colour. It also protects skin from the harmful effects of the sun.

When our skin is out in sunlight, our melanocytes make more melanin. This is to absorb more of the potentially harmful ultraviolet (UV) rays from the sun. This makes the skin look darker, or suntanned. A suntan is a sign that the skin is trying to protect itself.

If you have brown or black skin, you have the same number of melanocytes as people with white skin. But your melanocytes make more melanin. This means you have more natural protection from UV rays.

Moles are a group or cluster of melanocytes that are close together. They are sometimes called naevi.