What is the outermost protective layer of the skin?

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

Answer: (A)

The outermost protective layer is the epidermis. It’s made of keratinized, stratified squamous cells that form several sublayers, with the outermost portion (the stratum corneum) consisting of flat, dead cells rich in keratin. This thin, durable surface continually sheds and is replenished, creating a strong barrier that helps prevent water loss, protects against mechanical injury, and shields against microbes and UV exposure. The epidermis is avascular, getting nutrients from the underlying dermis. Just beneath it is the dermis, a tough, connective-tissue layer containing blood vessels, nerves, hair follicles, and glands, which supports and nourishes the skin. Under that sits the hypodermis (subcutaneous tissue), which is mainly fat and connective tissue that anchors the skin and provides insulation. So the epidermis is the skin’s outer protective shield.