Skin
Functions of the Skin
1. Resistance to trauma and infection.
How It Works: The skin is the most resilient organ when it comes to sustained trauma and infection. The epidermal cells contain a protein called keratin that give the epithelium its toughness. Most infectious organisms cannot get past the skin; they can only gather on the outer surface. The dryness and acidity of the skin, as well as the skin's defensive antimicrobial peptides, keep the number of infectious organisms in line. |
2. Other barrier functions.
How It Works: The skin acts as a barrier to water. It prevents the body from absorbing too much water while swimming or taking a bath, and it keeps the body from losing too much water. The epidermis shields us from many of the ultraviolet rays we are exposed to, as well as dangerous chemicals. It is susceptible to several drugs and poisons, however. |
5. Thermoregulation.
How It Works: The skin monitors body surface temperature through nerve endings called thermoreceptors. It retains heat and loses excess heat as needed, playing a role in both the warming and cooling of the body. In order to warm the body, it constricts blood vessels of the dermis, which keeps warm blood deep in the body. In order to cool the body off, it dilates blood vessels, which allows more blood to flow close to the surface and lose heat through the skin. If this isn't enough to cool the body off, sweat glands secrete perspiration. |
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6. Nonverbal communication.
How It Works: The skin is an important means of nonverbal communication. Our faces are very expressive and are a means of communication in and of themselves, and the general appearance of the skin, hair, and nails plays a big part in self-image and social acceptance. |