Which layer of the skin is known as the outermost layer?

The outermost layer of the skin is the epidermis. This layer serves as the first line of defense against environmental hazards, such as pathogens and UV radiation. It is composed primarily of keratinocytes, which produce keratin, a protective protein that forms a barrier. The epidermis also contains melanocytes, which are responsible for producing melanin, contributing to skin color and protection against UV radiation. Unlike the deeper layers of the skin, such as the dermis and hypodermis, the epidermis does not contain blood vessels; instead, it relies on the underlying layers for nutrient supply through diffusion. The effectiveness of the epidermis in its protective role is critical for overall skin health.