Which is the outermost protective layer of the skin?

• A. Epidermis
• B. Dermis
• C. Hypodermis
• D. Subcutaneous layer

Answer: (A)

The outermost protective layer is the epidermis. It is a stratified squamous epithelium that sits on top of the dermis and acts as the body's first barrier against environmental hazards. The outermost cells become filled with keratin and cornified, forming the stratum corneum, which provides a durable, waterproof shield that helps prevent water loss and blocks pathogens. Because the epidermis is avascular, it relies on the underlying dermis for nutrients and oxygen. Beneath the epidermis, the dermis supplies structural support with connective tissue, blood vessels, and nerves, while the hypodermis (subcutaneous layer) lies deeper, mostly adipose tissue that anchors the skin and insulates the body.