Which of the following describes the role of keratinocytes in the skin?

Keratinocytes play a critical role in the skin primarily by providing a waterproof barrier. These cells are the predominant cell type in the epidermis and are responsible for the synthesis of keratin, a protein that contributes to the skin’s protective properties. As keratinocytes move from the deeper layers of the epidermis to the surface, they become filled with keratin and undergo a process called keratinization. This results in the formation of a tough, protective outer layer that keeps moisture in and prevents water loss, which is essential for maintaining hydration and overall skin health.

The other options relate to functions that are performed by different types of cells or systems within the integumentary structure. For instance, color pigmentation is primarily the role of melanocytes, which produce melanin. Temperature regulation is managed by sweat glands and blood vessels in the skin. Secretion of sweat is done by sweat glands as well, which aid in thermoregulation. However, none of these functions directly apply to the role of keratinocytes, solidifying the choice of the role they play in creating a waterproof barrier.