Massachusetts State Board Esthetics Practice Exam

What is the characteristic of stratum corneum cells?

1. They contain nuclei

2. They are hardened and waterproof

3. They are actively dividing

4. They are filled with lipids

The correct answer is: They are hardened and waterproof

The characteristic of stratum corneum cells being hardened and waterproof is accurate because the stratum corneum represents the outermost layer of the skin, primarily composed of dead keratinized cells. This layer serves as a protective barrier against environmental factors, such as pathogens, chemicals, and moisture loss. The process of keratinization transforms these living cells from the deeper layers of the epidermis into dead, flattened cells that are filled with keratin, which provides strength and water resistance. The lipids present in the intercellular spaces of the stratum corneum further enhance its barrier function, preventing transepidermal water loss and keeping the skin hydrated. This combination of keratin and lipids is crucial for maintaining the skin's integrity and protecting against external stresses.