What’s It to Me? – What Your Skin Looks Like
What’s on Top: Epidermis

The epidermis is the outermost layer of the skin lying above the dermis.The epidermis is the outermost layer of the skin lying above the dermis. It is composed of several types of cells which show the layered nature of the overall skin structure. These cells are arranged in layers as follows: stratum corneum, squamous cells, and basal layer. The epidermis functions to protect the body, keep in body fluids, support healing, produce hair follicles and sweat glands, and protect the dermis and body organs from damage. This layer is related to skin cancer since most skin cancers develop from basal cells, squamous cells and melanocytes found here.

The stratum corneum is the uppermost layer of the epidermis. It is composed of keratinocytes which are very flattened in shape. These cells are filled with the protein keratin that results in the formation of a tough, waterproof coat.

This layer is continuously changing as dead cells slough off from the top and new cells from underneath move up. Millions of these cells are lost each day and some people estimate the body gets a totally new epidermis every 35 to 45 days.

The squamous cells form several layers and are primarily keratinocytes.The squamous cells form several layers and are primarily keratinocytes. They are somewhat flattened and irregular in shape. They also contain a protein called prekeratin. The upper few layers of these cells begin to develop thick walls and become more flattened. These cells will form the next stratum corneum cells.

The basal layer is the deepest layer of the epidermis.

The basal layer is the deepest layer of the epidermis. It consists primarily of a single layer of the youngest keratinocytes which divide very rapidly to replenish the squamous cell layer and stratum corneum. About 10% to 20% of the cells in this layer are melanocytes which produce the pigment melanin have many branches that extend among the surrounding cells. Melanin is discussed in more detail in the next section.

 

Next: Caught in the Middle

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