What is the Layer of Dead Skin Called?
The outermost layer of dead skin cells is called the stratum corneum. This layer acts as a protective barrier, preventing water loss and protecting against environmental damage. It's composed of 15-20 layers of dead keratinocytes, cells that have undergone a process called cornification, resulting in a keratin-rich barrier. This cornified layer is constantly shedding and being replaced by new cells from deeper layers of the epidermis. Many skincare products, such as facial scrubs, aim to remove or thin this layer of dead skin cells.
The stratum corneum is the most superficial layer of the epidermis, the outer layer of our skin. Unlike the deeper layers of the epidermis, which contain living cells, the stratum corneum consists entirely of dead cells. These cells, called corneocytes, are filled with keratin, a tough protein that gives the skin its strength and waterproofing properties. The stratum corneum is crucial for maintaining skin health and protecting the body. Its structure and function are summarized below:
- Composition: Primarily composed of corneocytes (dead keratinocytes) and intercellular lipids.
- Function: Protects against water loss, environmental stressors, and microbial invasion.
- Renewal: Constantly shed and replaced by new cells migrating up from deeper layers of the epidermis.
- Removal: Can be thinned or removed through exfoliation using methods like facial scrubs or chemical peels.
Several references support this information:
- Reference 1: States that the stratum corneum contains dead skin cells and can be thinned by various skin products.
- Reference 5: Explicitly identifies the stratum corneum as the outer layer of dead skin.
- Reference 7: Describes the stratum corneum as a layer of dead cells.
- Reference 8: Explains how dead skin cells form the stratum corneum (around 15-20 layers).
Other layers of the epidermis contain living cells:
- Stratum basale: The deepest layer, containing actively dividing cells.
- Stratum spinosum: Contains irregular, polyhedral cells.
- Stratum granulosum: Contains cells that begin to die and accumulate keratin.
- Stratum lucidum: A thin, clear layer found only in thick skin (palms and soles of feet). While these cells are also dead, they're not as prominent as those in the stratum corneum in terms of their overall function and being considered "dead skin".
