Which statement describes barrier function in the skin?

Which statement describes barrier function in the skin?

• A. The hair shaft
• B. The protective barrier of the epidermis; the corneum and intercellular matrix protect the surface from irritation and dehydration.
• C. The protective barrier of the dermis
• D. The sweat glands

Answer: (B)

Barrier function is the skin’s ability to protect internal tissues from irritants and to prevent water loss. The epidermis, especially its outermost layer called the stratum corneum, forms this shield. It consists of corneocytes (dead, flattened skin cells) embedded in a lipid-rich intercellular matrix. The lipids—ceramides, cholesterol, and free fatty acids—create a tight barrier that limits dehydration (trans-epidermal water loss) and blocks irritants from penetrating the surface. That’s why describing barrier function as the protective barrier of the epidermis, with the corneum and intercellular matrix protecting the surface from irritation and dehydration, is the best description. The hair shaft and sweat glands aren’t responsible for this barrier, and the dermis isn’t the primary barrier layer.

Barrier function is the skin’s ability to protect internal tissues from irritants and to prevent water loss. The epidermis, especially its outermost layer called the stratum corneum, forms this shield. It consists of corneocytes (dead, flattened skin cells) embedded in a lipid-rich intercellular matrix. The lipids—ceramides, cholesterol, and free fatty acids—create a tight barrier that limits dehydration (trans-epidermal water loss) and blocks irritants from penetrating the surface. That’s why describing barrier function as the protective barrier of the epidermis, with the corneum and intercellular matrix protecting the surface from irritation and dehydration, is the best description. The hair shaft and sweat glands aren’t responsible for this barrier, and the dermis isn’t the primary barrier layer.