Answer
The skin serves as an effective protective barrier for internal tissues and organs in the following ways:
1. Mechanically. The skin is dry and the tough keratinized cells of the stratum corneum protect aginst physical tearing and piercing
2. As a waterproof barrier. The corneous layer is an almost perfect waterproof barrier. It conserves body fluids and prevents us from becoming water-
logged.
3. The acid mantle serves as an effective bacteriocidal barrier-- pH of the skin is pH 4-pH6. Skin acids and certain peptides on the surface kill
infectious organisms
4. Skin pigments protect against UV radiation damage.
Work Step by Step
Although skin is almost waterproof, lipophilic substances can penetrate the epidermis. Nicotine, EDTA, and the hormones estrogen, and progesterone are some other substances that penetrate the cutaneous barrier more easily than hydrophilic substances and water.
