The skin is not entirely impermeable but acts as a waterproof barrier, primarily due to the presence of keratin, a strong protein found in the outermost layer of the epidermis. Keratin is insoluble in water, which contributes significantly to the skin's ability to resist water penetration.
This waterproof barrier is crucial for maintaining the body's internal environment and protecting it from external threats. However, the skin's permeability can vary depending on factors like the individual's age, health, and the specific substance in question.
For instance, certain substances like medications can be formulated to penetrate the skin through transdermal drug delivery methods. Also, the skin is not impermeable to gases like oxygen and carbon dioxide, which are essential for respiration.
The skin's permeability plays a vital role in maintaining overall health and preventing infections, while also allowing for essential functions like gas exchange and medication absorption.
