What skin layer is primarily responsible for water resistance?

The stratum corneum is the outermost layer of the skin and plays a crucial role in water resistance. It is composed of dead, flattened skin cells that are rich in keratin, a protein that provides strength and waterproofing. This layer acts as a barrier, preventing water from entering or leaving the skin.

The keratin in the stratum corneum helps to keep the skin hydrated by reducing transepidermal water loss, which is essential for maintaining skin health and integrity. By serving as the first line of defense against environmental factors, this layer helps protect the underlying layers of skin while ensuring the body retains moisture.

In contrast, the dermis contains connective tissue, blood vessels, and various glands but is not primarily responsible for the skin's water resistance. The epidermis encompasses the stratum corneum and other layers but lacks the specific properties of the stratum corneum that provide water resistance. The hypodermis, being the deeper layer composed mainly of fat and connective tissue, also does not contribute to the water-resistant function of the skin. Thus, while all layers work together to maintain skin function, the stratum corneum is key for water resistance.