Which skin structure is responsible for the waterproof barrier of the skin?

The stratum corneum is the outermost layer of the epidermis and plays a critical role in forming the skin's waterproof barrier. It comprises multiple layers of dead, flattened skin cells that are filled with keratin, a protein that provides strength and impermeability. This layer helps prevent the loss of moisture from the body and protects against environmental factors such as bacteria, chemicals, and physical abrasions.

The presence of lipids within the intercellular spaces of the stratum corneum further enhances this barrier function, creating a hydrophobic layer that is essential for maintaining skin hydration and overall integrity. Without the stratum corneum's effective barrier, the skin would be prone to dehydration and infection.

Other skin structures, such as the stratum spinosum, stratum germinativum, and stratum lucidum, contribute to the overall health and structure of the skin but do not specifically serve to create a waterproof barrier in the same way that the stratum corneum does.