The skin is made up of 3 layers known as the Epidermis, Dermis and the Subcutaneous:
- The Epidermis
The Epidermis is the outermost layer of skin and is the part you can see and touch.
It’s made up of several layers of cells, the outermost of which is called the stratum corneum (or horny layer). The layers can be seen clearly in the diagram of the skin.
The surface layer is composed of 25 to 30 sub-layers of flattened scale-like cells that are continually being exfoliated off by friction and replaced by the cells beneath.
The surface layer is considered the real protective layer of the skin. Cells are called keratinised cells because the living matter within the cell (protoplasm) has changed to form a protein (keratin) which helps to give the skin its protective properties.
New skin cells are formed in the deepest layer of the epidermis. This layer is known as the stratum basale. New cells begin to gradually move from this layer towards the stratum corneum to be shed. As they move towards the surface, the cells undergo a process of change from a round, living cell to a flat, hardened cell.
The layers of the epidermis from top to bottom are:
- Stratum Corneum/Horny Layer
- Stratum Lucidum/Clear Layer (only found in the palms on the hands and soles of the feet)
- Stratum Granulosum/Granular Layer
- Stratum Spinosum/Prickle Cell Layer
- Stratum Basale/Basal or Germinative Layer
- Dermis layer
The dermis is the inner layer of the skin. It’s tough and elastic and contains white fibrous tissue interlaced with yellow elastic fibres.
The dermis contains:
- Blood vessels
- Lymphatic capillaries and vessels
- Sweat glands and their ducts
- Sebaceous glands
- Sensory nerve endings
- The arrector pili muscles, which contract causing the hair follicle to stand up straight in cold weather to trap heat forming “goosebumps”
- Hair follicles, hair bulbs and hair roots
- Subcutaneous layer
This is the deepest layer of the skin and is located beneath the dermis. It connects the dermis to the underlying organs. The subcutaneous layer is mainly composed of loose fibrous connective tissue and fat (adipose) cells interlaced with blood vessels. This layer is generally around 8% thicker in females than in males. The functions of this layer include insulation, storage of lipids, cushioning of the body and temperature regulation.