What is Skin ? - Medical world

Skin is the largest organ of our bodies. Skin is very important as it covers and protects everything inside your body. It comprising about 15% of the body weight. It covers and protects everything inside your body. Skin holds everything together. It also protects our bodies , helps keep our bodies at just the right temperature and allows us to have the sense of touch. Skin is permeable and can absorb many things. Skin is a clear indicator of general health. Skin is also exposed to sunlight, and can suffer as a result. The skin has five layers in the outermost part known as the epidermis, as well as two layers beneath the epidermis: the dermis and the subcutaneous. The epidermis on the outside. This is made from layers of cells with a basal layer, which is always forming new cells through cell division. The new cells gradually move towards the surface, which takes 1-2 months.

The epidermis consists of three types of cells keratinocytes, melanocytes and Langerhans cells. Keratinocytes, the cells that make the protien keratin, are the predominant type of cells in the epidermis. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. It is always making new skin cells that rise to the top to replace the old ones. Most of the cells in your epidermis (95%) work to make new skin cells. The next layer down is the dermis. The dermis contains nerve endings, blood vessels, oil glands, and sweat glands. It also contains collagen and elastin, which are tough and stretchy. The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region.

Dermis is also full of tiny blood vessels. These keep your skin cells healthy by bringing them the oxygen and nutrients they need and by taking away waste. The third and bottom layer of the skin is called the subcutaneous layer. It is made mostly of fat and helps your body stay warm and absorb shocks, like if you bang into something or fall down. Subcutaneous fat acts as a shock absorber and heat insulator, protecting underlying tissues from cold and mechanical trauma. The subcutaneous layer also helps hold your skin to all the tissues underneath it. The loss of subcutaneous tissue, often occuring with age, leads to facial sag and accentuates wrinkles. Most mammals lack subcutaneous tissue because their fur serves as a shock absorber and heat insulator. Sweat glands and minute muscles attached to hair follicles originate in subcutaneous tissue.