Skin Health

Dermis Layer

The strength of the skin is due to the fibrous dermis. An outer layer beneath the basement membrane consists of tiny “hillocks” called papillae. They contain fine collagen fibers and are well supplied with blood vessels, nerves, and lymphatic structures. Beneath this layer is a far thicker one containing larger budles of collagen fibers running in several directions. The fibers, synthesized by fibroblasts, are made of cross-linked collagen and are strong and resistant to enzymatic attack. This layer also contains elastic fibers, blood vessels, nerves and lymphatic structures as well as specialized nerve endings and the various skin appendages, including hair, sweat and oil glands, and nails.

Except for the palms, soles, lips, eyelids, nipples, and parts of external genitalia, the mammalian body is usually covered with hair. In humans the hair is often thin and short and not readily seen on much of the body. Hair follicles are lined by epidermal cells. They form by a dimpling of the epidermis into the dermis. As the cells fill with keratin, they adhere to one another and form hair, which elongates as new cells form at the hair base. Melanosomes find their way into the hair cells, giving them color. From the wall of the follicle an oil gland provides a protective hair coating. Plugged oil glands form black heads, and if these become infected they produce acne. Cold or fear can stimulate the tiny muscle attached to each hair follicle to erect the hair.

posted by Margi @ 7:00 AM