👉 The term "epidermis" refers to the outermost layer of skin, which is composed of keratinocytes. These cells are responsible for providing a protective barrier against external stimuli and also play an important role in regulating the body's normal metabolism and function. The epidermis is divided into three main layers: the stratum corneum (the outermost layer), the stratum basale (middle layer), and the stratum spinosum (innermost layer).