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Some people have curly corkscrew hair, while others have thick, straight, shiny hair. A piece of hair may look simple, but it’s one of the body's most complicated structures. The hair follicle is the part below the skin, and the hair shaft is what you see above your skin. It protects your skin and traps particles like dust around your eyes and ears. If your hair gets damaged, it can renew itself without scarring. Female art students known as the Cropheads also adopted the style, notably at the Slade School in London.

Hair Shaft
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Hair Definition SLAM.
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The external hair is completely dead and composed entirely of keratin. Furthermore, you can cut your hair or shave without damaging the hair structure because the cut is superficial. Most chemical hair removers also act superficially; however, electrolysis and yanking both attempt to destroy the hair bulb so hair cannot grow.
Clinical Significance
Instead, the relatively sparse density of Afro-hair, combined with its springy coils actually results in an airy, almost sponge-like structure that in turn, Jablonski argues,[52] more likely facilitates an increase in the circulation of cool air onto the scalp. Further, wet Afro-hair does not stick to the neck and scalp unless totally drenched and instead tends to retain its basic springy puffiness because it less easily responds to moisture and sweat than straight hair does. Hair has its origins in the common ancestor of mammals, the synapsids, about 300 million years ago. It is currently unknown at what stage the synapsids acquired mammalian characteristics such as body hair and mammary glands, as the fossils only rarely provide direct evidence for soft tissues. All natural hair colors are the result of two types of hair pigments. Both of these pigments are melanin types, produced inside the hair follicle and packed into granules found in the fibers.
The Growth Cycle
At the end of this phase, which lasts about 2 to 4 months, another anagen phase begins. The basal cells in the hair matrix then produce a new hair follicle, which pushes the old hair out as the growth cycle repeats itself. Hair typically grows at the rate of 0.3 mm per day during the anagen phase. Hair loss occurs if there is more hair shed than what is replaced and can happen due to hormonal or dietary changes. Hair loss can also result from the aging process, or the influence of hormones.
At and following puberty, this hair is supplemented by longer, coarser, more heavily pigmented hair called terminal hair that develops in the armpits, genital regions, and, in males, on the face and sometimes on parts of the trunk and limbs. The hairs of the scalp, eyebrows, and eyelashes are of separate types from these others and develop fairly early in life. On the scalp, where hair is usually densest and longest, the average total number of hairs is between 100,000 and 150,000.

The hair in the nose and ears, and around the eyes (eyelashes) defends the body by trapping and excluding dust particles that may contain allergens and microbes. Hair of the eyebrows prevents sweat and other particles from dripping into and bothering the eyes. Hair also has a sensory function due to sensory innervation by a hair root plexus surrounding the base of each hair follicle. Hair is extremely sensitive to air movement or other disturbances in the environment, much more so than the skin surface.
Sensory information from hair stimulation enhances tactile ability. Autonomic nervous innervation primarily provides control of the arrector pili muscle. Contraction of these tiny muscles makes the hair "stand on end." This is likely a vestigial function related to fur; erecting the shafts served to trap air, conserve heat in cold climates, and cut a larger silhouette to intimidate rivals or would-be predators. Because hairs continue to enter the resting phase and then fall out, we are constantly losing hair. A healthy adult may lose about 70 to 100 hairs on their head per day.
Except for a few growing cells at the base of the root, the hair is dead tissue, composed of keratin and related proteins. The hair follicle is a tubelike pocket of the epidermis that encloses a small section of the dermis at its base. The human hair is formed by divisions of cells at the base of the follicle. As the cells are pushed upward from the follicle’s base, they become keratinized (hardened) and undergo pigmentation. Next is the telogen or resting phase of the hair cycle, in which the hair follicle is dormant, and growth of the hair shaft does not occur.
The hair papilla, which supplies the hair root with blood, is found inside the bottom of the hair bulb. New hair cells are constantly being made in the hair bulb, close to the papilla. The unwanted loss of hair, known as alopecia, is a widespread condition affecting both sexes, occurring in numerous patterns, and classified into non-scarring and scarring (cicatricial) subtypes. The sebaceous gland produces sebum, or oil, which is the body’s natural conditioner. More sebum is produced during puberty, which is why acne is common during the teen years.
The follicle is the primary structure from which hair can grow. The histological arrangement of the follicle is divided into outer and inner root sheaths. The follicle is lined by an inner and outer sheath that protects and molds the growing hair. The inner sheath follows the hair and ends just before the opening of the oil gland, or sebaceous gland. Another factor in human evolution that also occurred in the prehistoric past was a preferential selection for neoteny, particularly in females. The idea that adult humans exhibit certain neotenous (juvenile) features, not evinced in the other great apes, is about a century old.
The catagen phase begins with the end of the anagen phase and is characterized by a transition into quiescence. During this phase, which can last a few weeks, the hair follicle undergoes apoptosis-driven regression and loses about one-sixth of its standard diameter. The formation of a club hair, an important prognostic indicator in assessing hair pathology, also occurs at this time. If many hairs form club hair at once and are subsequently shed, it can give the appearance of thinning.