dead cells in a row.
hairs consist of horny cell layers of the skin, which are lined up like a thread. They are also, as the nails, the skin appendages. The hair root extends into the dermis and sometimes even into the subcutaneous tissue.
The human hair consists of the hair shaft, the hair root and hair bulb. The hair shaft is the part that protrudes from the skin. The hair root is anchored in the skin. It ends with a bulbous thickening of the hair bulb. The hair bulb is attached to the hair papilla of the skin from Connective tissue is. This gives the hair hold. The hair root is in the root sheath, the hair follicle is also called. Connected to this is a sebaceous gland that lubricates the hair. In addition, each individual hair is covered by a muscle and nerve fibers wound. The nerve fibers are very fine, they register even the slightest touch, such as a slight breeze. Then pull up the small muscles and creates the creeps.
The hair is made up of three layers.
The hair that is visible above the skin surface, is constructed in three layers:
are in the middle of the marrow cells the medulla also be mentioned. They often act like a sponge.
is fusiform To the medulla around a layer of horny fiber cells, which also is called Cortex. This fibrous layer is basically the main component of hair. Depending on how it is being used to determine the strength and elasticity of the hair. In the fiber layer contains the color pigments. To
is the fibrous layer around, protected like a pine cone, the hair by a cuticle. This cuticle layer, the cuticle is, although several layers, but also very thin. Because it is transparent, shine through this layer, the color pigments of the hair through.
hair is still a physiological function.
hair grow almost anywhere on the body to the skin fields. They protect the body from external pressures and the cold. However, this function is no longer so important. The head hair is still important. Protect them from excessive sun exposure. The hairs on the eyes, eyebrows and eyelashes, offer protection against the ingress of foreign bodies. The same is true of the hairs in the nose. They are designed to prevent inhalation of dust and small insects.
fashion and social status often determine the hairstyle.
In addition to these physiological functions of hair today, but most of all an aesthetic Fashionable and functional. Hair and hairstyles have often expressed in different cultures the social status of people. Often the hair shows today the membership of a particular group, such as punks. Commonly heard today, hair of the major cosmetics that mark the appearance of a person.
The hairs are produced before birth.
The development of the hair starts from the 6th Week of pregnancy. At this time, about 5 million hair follicles can be created. After birth, no new hair follicles add more. Although the man has as much hair follicles as chimpanzees, he did not so much hair. The reason is that not a hair is growing in every hair follicle. A hair follicle can, however, later in life develop several types of hair. Thus, the hair follicles collected in the face of a man on first with puberty to develop facial hair. The same applies to the pubic hair. are taken from
www.medizininfo.de
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