Keratinocytes make up about 90% of the cells in the epidermis and are responsible for producing keratin, a fibrous protein that provides strength, resilience, and protection to the skin, hair, and nails. In addition to keratin, keratinocytes produce lipids, which contribute to the skin’s natural moisture barrier, and other proteins that are involved in various skin functions.
The life cycle of keratinocytes involves a process called differentiation, in which they move from the basal layer of the epidermis to the surface, gradually changing their shape and composition. As they reach the surface, they become flattened, lose their nuclei, and form a protective layer called the stratum corneum, which is composed of dead, keratinized cells.
There are three main types of keratinocytes:
- Basal keratinocytes: These are the most basic type of keratinocytes. They are found at the bottom of the epidermis and are responsible for producing new keratinocytes.
- Spinous keratinocytes: These keratinocytes are found in the middle layer of the epidermis. They are responsible for producing keratin and lipids.
- Cornified keratinocytes: These keratinocytes are found in the top layer of the epidermis. They are dead cells that are filled with keratin. These cells eventually flake off, taking the keratin with them.
Keratinocytes play an important role in the health and appearance of the skin. They help to protect the skin from environmental damage, such as UV radiation and pollution. They also help to keep the skin hydrated and looking its best.
The suffix following “keratinocyte” indicates the type of cell responsible for producing a specific substance. In the case of keratinocytes, these cells synthesize keratin, while adipocytes are the cells responsible for creating adipose tissue, also known as fat tissue.