Skin's waterproof nature is crucial for our survival. It's not completely waterproof, but its ability to significantly resist water penetration is due to a combination of factors.
The Key Role of Keratin
The epidermis, the outermost layer of skin, contains a protein called keratin. This reference and this one highlight keratin's insolubility in water as the primary reason for skin's water resistance. This means water molecules can't easily penetrate this tough, protective layer.
The Importance of Lipids
Beyond keratin, this article emphasizes the role of lipids (fats) in creating a water-resistant barrier. These lipids are strategically arranged within the skin's structure, forming a robust seal that prevents water from passing through.
A Multi-Layered Defense
The skin isn't just a single layer; its structure contributes to its overall waterproofness. This resource describes skin as a "waterproof, flexible, but tough protective covering." This multi-layered structure, comprising the epidermis and dermis, provides a complex barrier against water.
The "Waterproof" isn't Absolute
It's important to note that skin's waterproofness is relative. While it significantly prevents water from entering, it also allows for the passage of water in the form of sweat (this article explains this). This balance is vital for thermoregulation. Additionally, prolonged exposure to water or damage to the skin's barrier can compromise its waterproof properties.
