Skin Structure The Epidermis

What is the epidermis? This is the top layer of skin Made up of 5 different layers each one has its own function Main function is to protect the deeper living structures from invasion and harm from the external environment

Each layer can be recognised by their different shape and function. Over about 4 weeks the cells move from the bottom layer to the top layer As they move through each layer they change shape and have a different function

Horny layer Also known as the stratum corneum This is the layer you look at These cells are dead and flat Thickness varies

Clear layer Also known as the stratum lucidum Made of dead, flat, clear cells Only present where there is a lot of friction Found on soles of feet and palms of hand

The Granular layer Also known as the stratum granulosum Cells in this layer are changing – look like granules Cells finish hardening they are now keratin

The Prickle layer Also known as the stratum spinosum Cells in this layer have spines or prickles Keratinisation starts – cells harden and flatten

The Basal Layer Also known as Stratum Germinativum Bottom layer Cells begin life in this area. Process is called mitosis (cell division) Fed from the dermis below Cells must push upwards from here

Melanin Produced by cells called melanocytes Gives skin its colour Protects against UV rays – tanning The amount will depend on race

Keratin Fibrous protein Found in tissues like outer layers of skin, hair and nails This is the tough guy with a soft heart Hard keratin protects Soft keratin allows things to be supple