The dermis is the second, or middle, layer of a person's skin. It contains fibers of collagen and elastin, which are important proteins. The collagen and elastin in this layer of skin form a durable mesh-like layer. The dermis also contains fibroblasts, which are cells important to the overall health of skin, small blood vessels called capillaries, and lymph nodes. Additionally, the dermis contains sebaceous glands, hair follicles, sweat glands, and nerves.
People cannot see the dermis because it is below the epidermis, the top layer of skin, and hidden from view. The fact that the dermis is hidden from view doesn't make it any less important, however. This layer of skin is thicker than the outermost layer and has the job of giving the skin its pliability and firmness. It also helps the body maintain its temperature and even sends nutrients to part of the epidermis. Since the dermis contains nerves, it also helps a person to recognize a range of sensations, including pain, touch, and warmth or cold.
The various parts of this layer of skin have important jobs to do. For example the proteins collagen and elastin help the skin to be resilient and stretchy yet, at the same time, firm. The fibroblasts in this layer of skin have an important role to play in the synthesizing of both collagen and elastin. In fact, this type of cell helps with the synthesizing of other molecules that support the structure of the skin as well. The tiny blood vessels that are present in this layer of skin help nourish it and provide necessary oxygen while the lymph nodes help to keep the skin protected from microorganisms.
The sebaceous glands in the dermis have an important job to do as well. They serve to produce an oily substance called sebum that helps to lubricate not only the skin, but also the hair that protrudes from it. The substance also helps make the skin somewhat waterproof. Sweat glands are important as well, as they help the body to regulate its temperature. In fact, some people call the perspiration the sweat glands produce air conditioning for the body; its very presence on the surface of the skin helps the body to cool itself down.
Interestingly, people often attempt to use anti-wrinkle creams on the surface of their skin and are disappointed with the results. This is due to the fact that wrinkles develop in the dermis, and most creams cannot penetrate that far into the skin. As such, collagen creams that are often sold for fixing or preventing wrinkles are unlikely to be effective.