Epidermis Research Paper

The human skin contains the epidermis, which is the farthest layer of skin, it provides a waterproof barrier and creates our skin tone. The dermis, beneath the epidermis, contains tough connective tissue, hair follicles, and sweat glands. The deeper subcutaneous tissue, which is the hypodermis, is made of fat and connective tissue.

In the the epidermis most of the cells are keratinocytes, they come from the deepest layer of the epidermis and with time makes its way to the surface of the epidermis. Keratinocytes once on the surface of the epidermis shed and are replaced by new cells which get pushed to the bottom. The outer portion of the epidermis contains the stratum corneum, is relatively waterproof and, when undamaged, prevents most bacteria,
Some areas of the skin contain more nerve endings than others such as the fingers and toes. Another part the dermis contains are the sweat glands which produce sweat in response to heat and stress. Sweat is composed of water, salt, and other chemicals. The dermis contains sebaceous glands secrete sebum into hair follicles. Sebum is an oil, that keeps the skin moist and soft and acts as a barrier against foreign substances.The hair follicles produce the various types of hair found throughout the body. Hair not only contributes to a person's appearance but has a number of important physical roles, including regulating body temperature, providing protection from injury, and enhancing sensation. A portion of the follicle also contains stem cells capable of regrowing damaged epidermis.The blood vessels of the dermis provide nutrients to the skin and help regulate body temperature. Heat makes the blood vessels enlarge, allowing large amounts of blood to circulate near the skin surface, where the heat can be released. Cold makes the blood vessels narrow, retaining the body's heat.

Below the dermis lies a layer of fat that helps insulate the body from heat and cold, provides protective padding, and serves as an energy storage area. The fat is contained in living cells, called fat cells, held together by fibrous tissue. The fat layer varies in thickness, from a fraction of an inch on the eyelids to several inches on the abdomen in some