What percentage of the epidermis is made up of keratinocytes?

The epidermis, the outermost layer of the skin, is primarily composed of keratinocytes, which are specialized cells responsible for the production of keratin, a key structural protein that provides strength and waterproofing to the skin. Approximately 95% of the cells in the epidermis are keratinocytes. This high percentage reflects their crucial role in skin barrier function and protection against environmental damage, pathogens, and loss of moisture.

Keratinocytes undergo a process called keratinization as they migrate from the lower layers of the epidermis to the surface, where they eventually die and form a protective, waterproof layer. By understanding that keratinocytes dominate the cellular composition of the epidermis, we can appreciate their importance in maintaining skin health and resilience.

In contrast, a lesser percentage of the epidermis is occupied by other cell types, such as melanocytes (which produce melanin), Langerhans cells (which are part of the immune response), and Merkel cells (which are involved in sensation). Therefore, the correct understanding of the composition of the epidermis emphasizes the predominance of keratinocytes in its structure and function.