What are the layers of the epidermis?
The epidermis has either four or five layers (or strata) depending on where it is.
There are two main types of epidermis:
Thin , which is found in places like your eyelids and consists of 4 layers (or strata).
Thick , which is found in areas that experience a lot of wear and tear (like the heels and soles of your feet).
The five layers (or four in thin skin) are:
Corneum - This is the outermost, roughest layer layer that consists of 20 - 30 layers of dead keratinocytes. They are dead, flat cells that are filled with a protein called keratin. They flake off the surface of the skin only to be replaced by new cells that rise up from lower layers.
Lucidum - This layer is only present in thick epidermis Lucidum is latin for clear, which makes sense as the Lucidium consists of 2 - 3 layers of clear, flat, dead keratinocytes
Granulosum The first layer to contain living cells, this layer has a grainy appearance due to the cells being moved up as they produce keratin.
Spinosum The cells in this layer look spiny when dried for a microscope sample because of tiny filaments that join the cells together.
Basal/e The bottom layer, this is where mitosis and most of cell production occurs. It also connects the epidermis to the dermis.
A useful, but ironic, way to remember these layers is with the following mnemonic:
Come, Lets Get Sun Burnt
Come - Corneum
Lets - Lucidum
Get - Granulosum
Sun - Spinosum
Burned - Basal/e
I hope this helps, and let me know if I can do anything else:)