Washington Esthetician State Board Practice Exam 2026 – Complete Prep Resource

The substance that surrounds the cells in the epidermis is lipids. Lipids play a crucial role in maintaining the skin’s barrier function and hydration. They create a protective layer that prevents water loss and keeps the skin hydrated, which is essential for overall skin health.

In the context of the epidermis, these lipids are primarily found in the extracellular matrix, which is the area between cells. This matrix is vital for holding the skin cells together and providing structural integrity to the skin. The presence of lipids is critical in preventing transepidermal water loss; when the lipid barrier is intact, the skin can retain moisture and maintain its elasticity and softness.

While collagens and elastin are important proteins found in the dermis that contribute to the skin’s strength and elasticity, they do not surround the epidermal cells. Keratin, on the other hand, is a protein that is produced by keratinocytes within the epidermis, primarily providing structural support and protection. It is most prevalent in the outermost layers of the skin but does not serve the same role as lipids in creating a surrounding barrier for epidermal cells.