What is the role of keratinocytes in the epidermis?

Keratinocytes play a crucial role in generating new skin cells in the epidermis. These cells are the primary type of cell found in the epidermis, making up about 90% of its composition. As keratinocytes mature, they undergo a process called keratinization, where they produce keratin, a key structural protein. This process leads to the formation of a tough, protective outer layer of skin that helps prevent pathogen entry and water loss.

Throughout their lifecycle, keratinocytes move from the basal layer of the epidermis, where they are produced, towards the surface. As they migrate upward, they gradually flatten and lose their organelles, eventually forming a hard protective barrier. This barrier is essential for maintaining the integrity and health of the skin.

This understanding helps distinguish keratinocytes from other cell types in the skin. While hormones, touch sensation, and melanin production are important aspects of skin function, they are attributed to different cell types, such as endocrine cells, Merkel cells, and melanocytes, respectively. The specific role of keratinocytes in generating new skin cells is fundamental to maintaining the skin's barrier and overall homeostasis.