The epidermis is composed of multiple layers, primarily made up of keratinocytes, which provide structural integrity and protection. The primary layers include the stratum corneum, stratum lucidum (only in certain body parts), stratum granulosum, stratum spinosum, and stratum basale. The stratum corneum, being the outermost layer, plays a key role in barrier function by preventing water loss and blocking the entry of foreign substances.
