What is the outer layer of skin called?

The outer layer of the skin is known as the epidermis. This layer serves as the body's first line of defense against environmental factors, including pathogens, chemicals, and physical abrasions. The epidermis is primarily composed of keratinocytes, which produce keratin, a tough protein that contributes to the skin's protective barrier. This layer also contains melanocytes, responsible for producing melanin, which gives skin its color and provides some protection against UV radiation.

The dermis, which is the thicker layer located beneath the epidermis, contains connective tissue, blood vessels, hair follicles, and glands. While crucial for skin structure and function, it is not the outermost layer. The hypodermis, also known as the subcutaneous layer, is found below the dermis and primarily consists of fat and connective tissue, serving as insulation and cushioning for underlying structures. The follicular layer is not a recognized layer of the skin; rather, it is part of hair follicle anatomy.

Understanding these distinctions highlights the role of the epidermis in overall skin health and its unique contributions to the integumentary system.