Massachusetts State Board Esthetics Practice Exam

What is the primary material that comprises 95% of the epidermis?

1. Collagen

2. Keratin

3. Elastin

4. Hyaluronic Acid

The correct answer is: Keratin

The primary material that comprises 95% of the epidermis is keratin. This fibrous protein is crucial for the structure and function of the epidermis, which is the outermost layer of the skin. Keratin provides strength, resilience, and water resistance to the skin, playing a vital role in its protective barrier properties. The presence of keratin in large quantities helps to safeguard underlying tissues from environmental damage, pathogens, and dehydration, making it integral to skin health. While collagen is important in the dermis for providing structural support and elasticity, its presence is not significant in the epidermis. Elastin serves a similar purpose in terms of elasticity but is also primarily found in the dermal layer. Hyaluronic acid, known for its moisture-retention capabilities, is present in the skin but not in such high concentrations as keratin in the epidermis. Understanding the unique roles and locations of these proteins helps clarify the importance of keratin in the epidermis.