What is the outermost layer of the skin called?

The outermost layer of the skin is called the epidermis. This layer serves as a protective barrier for the underlying tissues, safeguarding against environmental factors such as pathogens, UV radiation, and dehydration. The epidermis is composed primarily of keratinocytes, which produce keratin, a protein that helps to strengthen and protect the skin. This outer layer also contains melanocytes, which produce melanin, contributing to skin color and providing some protection against UV damage.

In contrast, the other layers mentioned serve different functions. The dermis lies beneath the epidermis and contains connective tissue, hair follicles, blood vessels, and nerves, playing a critical role in the skin's elasticity and strength. The subcutaneous layer, also known as the hypodermis, lies beneath the dermis and provides insulation and cushioning for the body. Thus, while each layer of the skin has its unique role, the epidermis is specifically identified as the outermost layer.