NACC PSW Practice Exam

The outer layer of skin is called the epidermis. It serves as a protective barrier against environmental factors such as pathogens, UV radiation, and physical abrasions. The epidermis is composed of several layers of cells, the outermost of which are dead, flattened keratinocytes that help to prevent water loss and provide an impermeable barrier. This layer is crucial for maintaining hydration and overall skin health. Unlike the dermis, which lies just beneath the epidermis and contains connective tissue, blood vessels, and hair follicles, the epidermis is avascular, meaning it does not contain blood vessels. The subcutaneous layer, also known as the hypodermis, is deeper than the dermis and primarily consists of fat and connective tissue, serving as insulation and energy storage. Understanding the structure and function of the epidermis is essential for recognizing its role in overall health and skin conditions.