Keratinotsüütides

Keratinotsüütides are the primary cell type found in the epidermis, the outermost layer of the skin. These cells are responsible for producing keratin, a tough, fibrous structural protein that forms the protective outer layer of skin, hair, and nails. Keratinocytes originate in the basal layer of the epidermis, known as the stratum basale, where they undergo continuous proliferation through cell division.

As keratinocytes mature and migrate towards the skin's surface, they undergo a process called keratinization. During this process, the cells lose their nucleus and organelles and accumulate increasing amounts of keratin. This transformation results in the formation of flattened, dead cells called corneocytes, which form the stratum corneum, the outermost protective barrier of the skin. This barrier prevents water loss and protects against mechanical damage and pathogen invasion.

The life cycle of a keratinocyte, from its birth in the basal layer to its shedding from the surface, typically takes about four weeks in healthy adults. This constant renewal process is crucial for maintaining skin integrity and function. Disruptions in keratinocyte differentiation or proliferation can lead to various skin conditions, such as psoriasis and eczema.