What is the dead layer of skin called?
The outermost layer of the epidermis, composed of dead skin cells, is called the stratum corneum. This layer, also known as the "horny layer," is crucial for protecting the underlying tissue from damage and dehydration. It's made up of 10 to 30 thin layers of continually shedding, dead keratinocytes. These dead keratinocytes, also called corneocytes, are strong and help form a protective barrier. The stratum corneum is constantly being renewed as new cells push up from the layers below, eventually becoming part of the stratum corneum and then shedding. Another layer of dead cells, the stratum lucidum, is found only in thick skin such as on the palms of the hands and soles of the feet. This layer is also translucent and composed of dead cells, but is located beneath the stratum corneum.
The stratum corneum is not just a layer of dead cells; it's a complex structure with a vital role in skin health. Its functions include:
- Protection: Acts as a barrier against environmental factors like UV radiation, chemicals, and pathogens.
- Hydration: Helps retain moisture and prevents dehydration.
- Regulation: Controls the permeability of the skin, preventing excessive water loss or absorption.
The continuous shedding of dead cells in the stratum corneum is a natural process essential for maintaining healthy skin. This process is sometimes accelerated by exfoliation, a method used to remove dead skin cells and improve skin texture.
Other Dead Skin Layers
While the stratum corneum is the primary dead skin layer, the stratum lucidum, found in thicker skin areas, is also comprised of dead cells. It's important to distinguish between these two layers. The stratum lucidum is thinner and less extensive than the stratum corneum.
