Disorders Of The Appendages

What is hair and what is its function
The hair on the head is not just there for decoration. It keeps us warm by preserving heat (we lose 90% of body heat through the head). The hair on the nose, ears and around the eyes protects these sensitive areas of the body from dust and other small particles. Eyebrows and eyelashes protect eyes by decreasing the amount of light and particles that go intothem. The fine hair that covers the body provides warmth and protects the skin. Hair also protects the body against injury.

Human hair is the hair shaft, which protrudes from the surface of the skin and the root, a soft thickened bulb at the base of the hair embedded in the skin. The root ends in the hair bulb. The hair bulb sits in a sac-hole in the skin called a follicle, from which hairgrows.

At the base of the follicle is the papilla, which takes place on the actual hair growth. The papilla contains an artery that nourishes the hair root. As the cells multiply and produce keratin to harden the structure, are pushed by the hair across the surface of the skin and hair shaft. Each hair has three layers: the medulla at the center, which is soft, the cortex surrounding the medullaand is the main part of the hair cuticle, the hard outer layer that protects the shaft.

Hair grows by forming new cells at the base of the root. These cells multiply to form a rod of tissue in the skin. The rods of cells move upward through the skin, as new cells form beneath them. As you move up, they are off from their supply of nutrients and begin to form a hard protein called keratin in aprocess called keratinization. As this process occurs, the hair cells die. The dead cells and keratin form the hair shaft.

Each hair grows approximately 1 / 4 inch (6 millimeters) every month, and continues to grow for up to 6 years. The hair then falls out and another grows in its place. The long hair of a person depends on the length of the hair growth phase. Follicles are active for 2 to 6years after resting for about 3 months. A person becomes bald if the scalp follicles die and no longer produce new hair. Thick hair grows out of large follicles; narrow follicles produce thin hair.

Hair color of a person is determined by the amount and distribution of melanin in the cortex of each hair (the same melanin that exists in the epidermis). Hair also contains a yellow-red pigment;people with blond or red hair have only a small amount of melanin in their hair. Hair becomes gray when people age because pigment no longer forms.

What are the nails and what is its function
The nails are developed in the deep skin folds of the toes and hands. As epidermal cells below the nail root move up to the surface of the skin, increase in number and those that are closest to the rootof the nail is flattened and compressed. Each cell is transformed into a thin plate, these plates are stacked in layers to form the nail. As with hair, nails are formed by keratinization. When the nail cells accumulate, the nail is pushed forward.

The skin under the nail is called the matrix. The largest part of the nail, the nail plate (nail plate), it looks pink from the network of tinyblood vessels in the underlying dermis. The area whitish crescent at the base of the nail called the lunula.

The nails of the fingers grow four or five times faster than the nails of the toes. Like hair, nails grow faster in summer than in winter. If a nail breaks, will regrow if the matrix is not seriously injured. White spots on nails are usually due to temporary changes in growth rate.Possible skin disorders, hair and nails

Here are some of the things that can affect the skin, nails and hair.
Dermatitis

Medical experts use the term dermatitis refers to any inflammation (swelling, itching and redness) of the skin. Several types of dermatitis, including:

Atopic dermatitis, also known as eczema. Dermatitis is a common hereditary causes an itchy rash primarily on the...