Principle

The basic principle of laser hair removal is the “photo thermolysis selective. ” The laser causes localized damage by burning the black areas emitting hair without burning the rest free ipad of the skin . The light is absorbed by the target substances (in hair removal is melanin) with high affinity to this wavelength, and which consumment by the heat energy absorbed.
Laser hair removal targets mainly the melanin . There are two types of melanin: eumelanin (which gives skin and black hair) and pheomelanin (which gives red hair, the colors of Asian skin and freckles).
Less hair contain melanin, the laser is less effective. For this reason, people with gray hair, red or blond are not good indications for laser hair removal.
On the other hand, the skin contains more melanin, the lower the laser reaches the difference between the skin and hair. For this reason, black people or very dull skin can benefit from treatment with traditional lasers (Alexandrite type). For black skin, it has been developed specific lasers in the infrared between 800 and 1064 nm. 810 nm lasers, often diode can, lengthening the time of application of energy, hair removal dark skin. Infrared lasers or 1064nm Nd: YAG has a lower affinity for melanin. This lower affinity preserves dark skin while keeping a certain efficiency of the hair (especially as the hair on black skin are highly concentrated melanin). These lasers typically require a few more sessions, but can treat black skin. Some argue that these lasers allow a hair of tanned skin while tanning must recuse patients because it is a cons-indication temporary (less effective laser for hair away from its target, increased pain, increased risk of burn ).
Light skin and dark hair is the best combination for laser hair removal. For other phototypes , special lasers or electrolysis will be offered. The results are, for example ultrasound, user-dependent. Ie with the same machine, two different doctors have different results. The choice of doctor is as important as the choice of the laser. Moreover, whether for hair removal by laser or flash lamp, it is a medical procedure, as stipulated in Article L. 372 of the Public Health Code as amended by Order chiropractic marketing of January 6, 1962. Any other person using a laser or flash lamp in order to achieve hair removal illegally practicing medicine. ²
Laser parameters

Many wavelengths of laser energy are massage in Seattle used for laser hair removal. Since the visible light up virtually the infrared . These lasers are generally designated by the type of wavelength they produce (measured in nanometers, nm):
Argon: 488 or 514.5 nm
Ruby: 694 nm
Alexandrite: 755 nm
Pulsed diode array: 810 nm
Nd: YAG: 1064 nm
Nd: YAP: 1079 nm
flash lamp which is not in itself a laser using the spectrum from 600 to 1000nm about the devices varies.
Lasers argon and ruby are practically used. The ruby would be an alternative for clear skin (phototype 1) Laser Alexandrite is the most widely used. It was at 755 nm photons that are most likely to be absorbed by the hair as other structures of the skin. This is the best choice for skin phototype 1-4. It no no hair removal can also be used for photype 5. The laser diode has as main advantage of being cheaper to buy than How to Lose Weight Fast lasers and alexandrite NdYag. They are versatile, but are generally less powerful, and therefore the maximum diameter of the spots are smaller, they are slightly more painful than the alexandrite lasers. Simpler and lighter, they can be transported from one place to another. It is a good alternative for skin phototypes 4 and 5, but given the size of spots, supermarkets are often treated worse. The laser NdYag is the only laser that can treat black skin, treatment is more painful but very effective. More recent use in hair removal, laser Nd: YAP coupled to a pulse train can treat all skin phototypes virtually painless.
The flash lamps are devices that have only one advantage: the price for the buyer. If alexandrite lasers, diode and even NdYag can handle virtually everyone with excellent results, the flash lamp can often produce a partial treatment. Compared with the laser, they will always be more dangerous and painful as trying to get to coat with the same laser fluence, it will always pull more strongly. Even pulling harder, they will often much less effective. They are never the best treatment, regardless Translation Services of skin phototype.
When buying a flash lamp costs between 5,000 and 25,000 euros. Diode lasers cost between 20,000 and 40,000 euros. NdYag alexandrite lasers and the most powerful now cost between 80,000 and Denver Divorce Attorney 100,000 euros. This is the only reason flash lamps continue to be sold.
The diameter of the laser beam (spot) is also important. It should normally be four times larger than the target is deep. Most lasers have a round spot of 8-18 mm.
The fluence or energy per unit area is an important consideration. It is measured in joules per square centimeter (J / cm ²). Another important parameter: the irradiance , which reflects the rate at which energy is delivered (W/cm2).
The repetition rate has a blu cigs coupon cumulative effect. Take 2 or 3 pulses on the same target with a specific time period between denver car accident lawyer each pulse can improve the heating zone.
Cooling of the skin can increase the influence and reduce pain. Therefore generally used a cryogenic spray or an air conditioning system associated with the handpiece of the laser.
The spacing of the laser hair removal sessions depends on the speed of hair growth and function of the treated area. The Orlando personal injury attorney face generally requires, for the first sessions, intervals of 3 to 5 weeks. For areas of the body, there are spacings of 4 to 10 weeks for first meetings. It’s the hair cycle that controls the spacing between sessions. Laser treatment effective conduit, session after session, with a bit of pushing more and more slowly, more and finer, more and more clear, more and more rare. There are areas easier to treat than others. The simplest: underarms, bikini, half leg where the hair is quite large and pigmented. The more complex the knee, thigh, face, in which the hairs are finer entry and colorful little less receptive to the laser energy.
Complications and side effects

The main side effect is the risk of burns 1 when the laser is heating area of skin rich in melanin if it is tanned. Darker skin, but not tanned, can benefit from laser hair removal with laser diode type-specific or extended pulse Nd: YAG laser. These lasers have less affinity to melanin and may affect the concentration of melanin in the hair, with minimal impact melanin in the skin. The cons-tan electronic cigarettes is formally indicated if the skin is tanned. It should protect themselves from sun exposure between 15 days and 3 weeks after laser hair removal (use of sunscreen type sunscreen, index 50 or higher). Most burns are laser-like first degree or second-degree light. They evolve but usually well back to normal can take several months. It should remind patients that, in some rare cases, the burn can leave a permanent depigmentation. Burns on dark skin or the mere passage of the laser without burning a true dark skin can cause an inflammation phenomenon with the development of hyperpigmentation can be extremely long to disappear. Hair removal lasers Mediterranean skin, if it is very effective, should be no exception for caution vis-à-vis the tan. The laser hair removal must not pass over areas tattoo so as not to cause deep burns by accumulation of energy in the pigment of the Crossfit Denver tattoo. Lasérisés tattoos are usually altered and cause healing complications. Finally, laser hair removal should not be used on skin with inclusions of explosive material (powder gun for example). It is important that the doctor do a search for healing disorders or coagulation disorders before starting a session of laser hair removal so as not to cause bruises or scars. certain medications (anti-epileptics, antibiotics …) can increase the sensitivity of laser skin and cause burns at doses normally mundane. It should be noted taking any medication the doctor lasers. Medication for acne as Accutane ® may increase the risk of abnormal scarring (keloids or hypertrophic scars). They must be stopped more than 6 months before starting a laser hair removal. In principle, n’épile not pregnant or lactating women. No birth or abortion has never been described, but should apply a precautionary principle. Many authors indicate no risk during pregnancy. Burn during pregnancy may however complicate the management and can eventually grow poorly. It is not safe to expose patients to this risk, although very rare.
Other applications

Some lasers are also used to remove tattoos Ex: Nd: YAG laser Q-swiched or vascular spots, including birthmarks (or wine stains). It normally uses a pulsed dye laser.

Waxing different times and societies

Antiquity
Ancient Egypt
In the ancient Egypt , the priests and pharaohs full body waxing. This would be a distinctive mark to signify purity. The hair was indeed seen as unclean.
[Ref. required]
Ancient Greece
The pubic hair was set for women in the classical period, with a view to avoid anything that might make them like men 1 .
Methods
At the beginning of the Christian era , the Carthaginians were already familiar with the tweezers, but also used the resin . Tertullian attributes this practice to Greek influence 2 .
In the West
Hair removal, new body mode
The method of hair removal for underarms , the pubis and the torso has recently taken a large force. [ref. needed] It probably comes from both the middle of the sports and sportsmen and women of the world of cinema. Indeed, to escape the censorship laws that prohibited showing any body hair so that we can show the genital area (Hays Code), the pornographic film industry has used hair removal. Finally, countries Muslim culture has always resorted to body hair removal [ref. required] , the current population movements have led to a mixing of cultural influences that may also play a role.
We [who?] often mentioned to justify the reasons of hair hygiene, in fact, these choices influenced by fashion and etiquette.
The method of hair removal is also supported by all the followers of body care and promoters of cream care, and especially by the cosmetics industry that sees a potential for profit. [ref. required]
Male hair removal
Male hair removal, which had fallen into disuse, is a fairly recent phenomenon since the 1990s, [ref. needed] men simply far to adjust the hair on their faces in fashion [ref. required] , by cutting their beards , or by skimming more or less completely.
In recent decades, advertising uses the sensuality of male models to advertise products such as perfumes , underwear , etc.. The vast majority of campaigns present models without hair or beards, and creating a method of hair removal male full.
In sports and in particular cycling, wrestling, tennis, football and rugby, a hair removal is recommended. Indeed, at a sports equipment including clothing are tight to the skin (called “tight”), the friction of certain textiles against the skin can cause irritation. On the shaved skin, hair does take longer in the meshes of textiles. For this reason some advise sporting a hair of certain body parts.
Types of hair removal

Detail of the Birth of Venus of William Bouguereau (1879)
The facial hair removal
The facial hair removal eliminates the down that covers the skin of the face.
In women, the fine can appear frequently on the chin, cheeks and upper lip. At the time of menopause , hormonal Joann Fabric coupons changes can develop this down.
In men, the hair is used for hair growing in the ears, nostrils and to separate more clearly the two eyebrows. It is also an opportunity to get rid of the beard term (and other facial hair) to avoid regular shaves.
The waxing of the legs
Hair removal underarm
Hair removal from armpits does not limit the odor, but gives a more aesthetic deemed by some companies in this part of the body. Today in the West and in Muslim countries, most women pluck or shave their armpits. Men sometimes do well.
Pubic hair removal
The bikini, relatively new in the West [ref. required] , is designed to remove hair that exceed the swimsuit .
For hair removal called “metro ticket” or “American”, the hairs are removed in forms more or less desirable: either a simple rectangle close to the forex trading system edges very sharp, or other forms to make the hairs as discrete as possible.
The Brazilian hair removal is a fairly low-cut hair, which retains a thin strip of hair and a small triangle in front. It allows you to wear swimsuits very close.
Total hair removal
Complete hair removal leaves no hair. We [who?] accused him of impoverishing the hair and reveal the scars . Many techniques to achieve total eradication of the hair, hair removal laser hair removal by electrolysis, which, by destroying the hair bulb, leaving the skin without shadows caused by gray hairs under the skin as with other methods hair removal.
Modes

Different methods exist to remove hair. Does not however immune to problems caused by hair removal (risk of infection, ingrown hair regrowth, cuts or micro-trauma in particular).
Temporary methods
The tweezers
Ancient technique, the Tweezing remains the most popular hair removal method [ref. needed] because of its nature simple, fast, convenient, versatile and very economical. The tweezers is the tool of choice for finishing eyebrows, underarms, bikini line and legs, as its accuracy is unsurpassed. However the tweezers can not pluck an individual to large areas of skin.
The razor
Articles: shaving and razor .
Fast and efficient, the razor is one of the favorite means of cutting hair [ref. needed] . Perfect for legs and underarms, it is not designed for the bikini. [ref. needed] It is advisable to use the foam to prevent cuts and special drying. However, shaving must be very regular (about once every two days) and the hairs that seem to push harder because they are beveled 3 .
The electric epilator
This result provides a perfect and lasting [ref. needed] . Slower than the traditional razor, it is ideal for the legs. The electric epilator hair wraps up the tear with its bulb. But it’s still relatively painful especially during the first few uses.
The wax
Strips of wax can pull the hairs with their roots. They are used hot or warm to dilate the pores of the skin and make it easier and less painful pulling. They can also be cold. Only down side is quite sports physical therapy painful. Therefore let hair grow before another waxing is really effective with long hair. However with a very thin application is effective on fine hairs. The waxing allows hair growth after about three weeks and has the advantage of being less painful than electrolysis.
Depilatory creams
Depilatory creams use a derivative of sulfur to dissolve the hair at the skin and to remove it without pain. However, this method requires a repetition of the gesture more common than waxing since the hair root trottinette freestyle is not torn, it pushes faster.
The mower
Quick and painless method that cuts the hair flush with the skin. It involves a regular action, however, as far as the razor. Unlike the latter, it does not irritate the skin and prevent ingrown hairs. This device also has the advantage, depending on model, can have shoes for the size of the remaining hair with respect the jersey.
The wire
This method is mainly used for facial hair removal, it is to tie a knot with a small wire and stretch on both sides of it while scanning the surface of tweezers. It is very effective on down and remove the hair and the bulb and therefore can slow regrowth of it.
Sustainable methods
Depilatory lotion
Some depilatory lotions, newly placed on the market, certainly have the role to remove the hair, but also have an inhibiting effect on the bulb. They can then delay the hair growth, or even stop it if the product is regular. This method has not proven and seems risky to mucous membranes [ref. needed] .
Permanent hair removal
Methods to permanently eradicate the hair can be grouped into two broad classes:
The oldest, some might say “most effective”, hair removal or electrolysis needle.
The latest: the technique to light. This implies that the laser technique and the technique IPL (Intense Pulsed Light).
Electricity
It involves introducing a needle (almost the thickness of the hair) in the hair canal, and a high frequency current burns the matrix. This method was already used at the beginning of xx th century , only it is the galvanic current was the result vector. Today, thanks to very fine needles and the current much better studied, well applied, it has the advantage of being radically from the first session, regardless of the color of the hair, its growth phase or skin color. It is better to treat hair thick enough for incorporating the needle without damaging the hair canal. It is therefore not recommended for sleeping bags. This method can cause micro skin burns. Healing is slow (several weeks) and may ultimately leave a mark. The major drawback is probably that the treatment is carried out hair by hair with discomfort of pain may be important depending on the area treated. Anesthetic creams are ineffective because they have an effective anesthetic for maximum 3 mm in the skin tissue. Now it is common to penetrate with the needle up to 6 mm. Treated areas are more than 10 cm ² per session, if the hair density is important.
Despite these many disadvantages, this method is advisable when others have proven ineffective. Like electrolysis, laser hair removal is performed by a medical specialist.
The laser hair removal
This is an ad hoc method of hair removal designed to burn the hair follicle to prevent hair regrowth.
The pulsed light
The idea is to project onto the skin, previously shaved, flashes of light radiating in the infrared . The dark hair absorbs heat from the lightning travels up the hair root and burns the hair follicle where it operates.
This hair removal method works with the dark hair on light skin. Darker skin (eg due to a tan) flashes of light can make painful because the skin also absorbs the heat that passes through the melanin.
This method of hair removal involves regular sessions every 3 to 6 weeks for at least a year. Do not pull the hair between two flash bulbs in order to preserve to help remove them during the application of light.
Benefits and harms of hair removal

Main article: hair .
The presence of variable hair is natural and generally in all mammals including humans land belongs. Even if they are ignored, the hair has different functions that opposes hair removal [ref. needed] . This type of account is usually completely ignored by supporters of the hair and the consequences of permanent hair removal are just as important.
In his essay From hairy to smooth: history and aesthetics of intimate hair removal , Jean Da Silva writes about male hair removal that “disrupting the order and the kinds of distinctive pattern in which the male is known as hairy and the feminine as smooth, hair removal, in its full version in particular is seen as an attack on anthropological and cultural landmarks, and as a sometimes negatively evaluated deviance, a sign of moral drift, sometimes a positive sign of a desire for freedom of body ” .

Formation of a hair

The hair, also called hair shaft, is rooted to about 4 mm under the skin (dermis). The exoskeleton is formed within a hair follicle , invagination of the epidermis in contact with a papilla dermal vascular. The area in contact with the papilla, hair matrix called, consists of keratinocytes and melanocytes that multiply rapidly by mitosis successive one .
Keratinocytes harden to form the hair shaft and then die. The hair bulb contains a melanocyte to thirty keratinocytes. Melanocytes transmit melanin to keratinocytes: the hair shaft grows so until the disappearance of pigmented melanocytes with age. [ref. required]
The hair follicle is related to a sebaceous gland or more and with a little smooth muscle, the muscle also called arrector muscle piloerection .
Genetics and body hair

Some genes code for proteins that are important for keratin . In mice a defect of such a gene (TGFα gene) leads to structural abnormalities of the skin and follicles, wavy coat, whiskers ( vibrissae ) alormalement curly (at birth), often also with inflammation of the cornea that occur with age 2
Role of hair

The coat extends the sensitivity of the body, allowing for example the detection of very small insects moving on the skin (in this case it is the larva of a bug , Vegetarian)
The hair of mammals have very different functions.
When it comes to fur or fur, the function most commonly accepted is that of thermal insulation , made ​​necessary by the homeothermy of mammals. It may be noted that the birds, which are the reputation management second warm-blooded vertebrate clade, have a similar structure, the pen , which performs the same function. The color and pattern of the coat are also signs of recognition or intraspecific can play a role of camouflage in some species.
However, there are many types of hair, and not all have this feature.
Many mammals have on the snout, near the mouth with long hair (the whiskers ) that have a role in sensory complex. Vibrissae are found especially among Carnivores , and Rodents who are able to move their whiskers in three dimensions, with protraction-retraction movements and the possibility of torsion (up to 100 °) that appear to play an important role in the use of whiskers as sensory receptors, passive and active 3 . Experience has been to move the whiskers of anesthetized rats and to observe the electrical response of neurons of the first order in the trigeminal ganglion , the latter have a “repertoire of responses that could not be inferred from their responses to stimuli deviation passive ” . Individual neurons respond differently in four type events: movement neuron whip or whipped contact with an object, moving object against the pressure and sensation of detachment from the object. The brain seems to be well informed about the precise position of the vibrissae and their movements 4 , 5 , 6 .
Hair, hair and other appendages appear to contribute to the detoxification of the body (unless the liver or kidney ), but significantly for animals that produce a lot of hair or who suffer frequent moults. It includes, for example, some toxic substances such as lead , the mercury or the arsenic absorbed by the individual through food or breathing in the months or years earlier. Morphological examination, serological and chemical hair or human hair to medical monitoring or is experienced in the years 1960 to 1970, for example to retrospectively assess exposure of individuals to toxic heavy metals, but the means ‘analysis does not sufficiently accurate results for organic molecules to extend the technique to drugs. It became possible from 1980 (assay more sensitive and more specific, thanks to the radioimmunoassay and gas chromatography / mass spectrometry , which in theory possible to hcg diet drops reconstruct the recent history of an individual terms of exposure to toxic drugs, drugs, etc.. After carefully washing the sample to avoid the risk of external contamination.
In humans, the hair is now relatively small compared to the average mammal. The role of thermal protection seems minor. Presumably it is important for the only area of ​​the body always covered with a large hair, the top of the head (hair). However, this is an assumption that deserves verification.
Under the arms and around the genitals hair seem to have the function to reduce the heat and inflammation, as well as the evaporation of perspiration , and perhaps the distribution of hormones . [ref. required]
The hairs constituting the eyelashes and eyebrows seem to have a role in protecting the eye against dirt and sweat 7 .
In the ears and nose, hair seem to play as a filter and alert in case of penetration (insect, object …). Certain stimuli trigger hairs of the nose for Wire Shelves example, the sneezing .
Hair Brush

Many fine animal hair ( sable , squirrel (Squirrel Northern), mongoose , polecats ) are used to make brushes for artists. According to their characteristics (strength, flexibility, nervousness, ability to absorb water, etc..), They will be used for technical fluids ( watercolor , gouache ) or paste ( oil paint , acrylic paint ).
In plants?

The equivalent of the hairs ( trichomes ) exist in many plants with poorly understood roles, sometimes protective and eventually transformed into thorns or stings (eg nettle ). In some cases the hairs appear to play an important sensor of particles or sensors nucleating the water dew [ref. needed] .
Analysis of hair (or hair)

Analysis for identification purposes: The hair of mammals, which can be harvested from such traps scotch ‘is used by naturalists to identify animals (species) 8 or even individuals within a population, via the genetic information ( DNA ) they contain the individual or population to which it belongs.
In particular one of the techniques used:
-In zoology , to track animals become rare or difficult to observe ( wolves , bears …);
-In criminology (as hair), to search for clues, or even evidence.
Toxicology and ecotoxicology or criminal police, the analysis of lead , of mercury , of arsenic , etc. in the hair or hair to identify poisoning by these metals.
In medical and veterinary traditionally been considered as the strength and shine of the hair of an animal or of human hair could provide information on health status.
Studies have focused on trace elements and metals traces found in the hair or fur. Some have shown that the average rate in some essential trace elements is lower in patients affected by certain diseases, or toxic elements in the rate increased in others, or sometimes reduced (for example, less mercury present in the hair Autistic babies 9 , but in their brains) Hair analysis can secondarily contribute to the diagnosis, including post-mortem of specific diseases or poisoning.
Statistically significant associations were also found between the results of analysis of hair and some demographic variables. For cons, the correlation between the presence of essential elements in HDMI switch the hair of animals and these same elements in the organs is rarely verified 10 .
The margin of error in the analysis can be significant 11 . In the medical field, standardization and certification of laboratories for the analysis of hair, is being organized 12 .
Anti-doping can use hair or hair in order to find the trace of a chronic or repeated doping (consumption profile over several months or years, depending on the length of the wick available). The identification of anabolic steroids in hair has been a few scientific publications. A study recently made ​​a point of reference physiological values ​​of testosterone (radioimmunoassay, conventionally used for the determination of free iPhone ringtones plasma testosterone). 100 mg of hair taken sufficient. This study used the hair collected from 25 non-sports subjects (four children, nine women and 12 men). Samples, washed and dissolved in the hot soda . Rates ranged from 0.6 to 2.7 pg / mg in children, and 1.8 to 6.4 pg / mg in women, for 3.6 to 23.3 pg / mg in men . Any result above 30 pg / mg suspect must leave (after confirmation by the technique of analysis which is the reference gas chromatography coupled with masseou spectrometry GC / MS ). This mode of analysis allows quick and easy quick results for a large number of samples, and thus could be used to fight against doping 13 .

“Memory” Toxicological
The hair is a tissue growth more or less regular, and free of metabolism after its own synthesis. But it can adsorb certain products.
This double feature explains that:
The internal content of a hair, such as mercury or lead trace ( stores or reveals) a contamination of the body of the individual when he produced the part of the hair that was analyzed.
It was thus possible to assume that in retrospect Beethoven died of lead poisoning , from analysis of strands of hair that had been preserved after his death 14 .
Guyana contamination mercury Amerindians Wayana the mercury miners was followed by analysis of their hair 15
The study reports the levels and isotopic (eg, deuterium and the oxygen ) in the hair of the year help to understand the migration of some species (eg bats 16 ) Moulting of bats occur annually driven by hormones. All bats in temperate regions are driven by a year, always in the lodging of reproduction 17 and again at the end of breeding season for females … and a few weeks for males. The footprint isotope of these hairs is characteristic of the area where the animal lived at the time of moulting.
Studies of this type have also been clarified ways and migration strategies for migrating species (butterflies, birds European sedentary …), to better understand the ecology and the use of certain biological corridors, their life history, elements useful for conservation biology . The isotopic labels can a priori to follow a variety of animal species in a variety of habitats, which is “revolutionizing the way we create links between the phases of the annual cycle of migratory animals. However, researchers must be cautious in applying isotopic methods ” 18 .
Disease of the hair

Hirsutism : excessive hair growth, or the whole body or in an unusual place, usually induced by a hormonal disorder.
Ringworm : infectious disease causing loss of hair in a specific location of the body.
The pilonidal disease (from the Latin “pilus” hair and “nidus” nest) is a benign and common. The term ” sacrococcygeal cyst “, long used seems inappropriate now 19 .
Ingrown hairs: more common after shaving or hair removal and visible on the surface of the skin, they emerge from their follicles but continue to grow under the skin thus deviating from their normal route (outside the skin). They are usually because of inflammation or of infection : folliculitis , abscesses , …
Abnormal forms, with curved hairs or “corkscrew” . Associated with purpura tropic hair or petechiae or scurvy , they may be accompanied by a fine hyperkeratosis pilaris. They reflect a deficiency in Vitamin C 20 ). Scurvy as it existed among the sailors fell, but the lack of vitamin is common in the alcoholic subject malnourished, socially isolated or in case of restricted diet or unbalanced in some psychiatric patients ..
Piloerection

Main article: piloerection muscle .
In many of the mammals [ref. required] , each hair is associated with a muscle called piloerection muscle (or muscle arrector). This allows the hair to stand up in various situations. In cases where the hair is important, general cheap car insurance piloerection of the hairs causes a thickening of the hair and increases its insulating power. There is actually a piloerection when the body temperature decreases. In humans, this reflex is also observed, although its role has a priori no major influence in the thermal insulation due to the low hairiness. This effect is responsible for goose bumps .
One can also see a piloerection in response to various stresses. In humans, fear can lead to significant piloerection. In some mammals, it is possible that the piloerection subsequent attack by a predator allowed by the rapidly increasing volume of the coat, a predator of that intimidation. This is what can be seen in some cats, like the domestic cat.
By extension, in common parlance , a person can very unpleasant “horripilate” or you “bristle hair.”
The hair in human culture

In all cultures the hair, a sign of puberty , is synonymous with masculinity , while the smooth skin is synonymous with femininity (but this ” smoothing “is most often achieved through the waxing ).
In addition, in many cultures, the development of hair shaved and the opposition (smooth – smooth) / hairy – hairy were involved in many considerations aesthetic but also moral or religious . Here are some examples:
In Greek , the hair is not distinguished from the hair . Indeed, they are referred to as both trichos . And one of the causes of the schism East / West seems to lie in the fact that the Byzantines (as the Greeks) proscribed shaving while the Romans themselves, forbade the beard .
Likewise English where hair refers to these two types of training. And as shown by the famous rock opera Hair its free development went hand in hand with sexual liberation .
under the old regime we know the importance of barbers who also surgeons , as Figaro distributed the bleeding but also the sweet notes
[Ref. needed] .
in Afghanistan , the Taliban when in power, required:
1 ° the beards (for men of course),

In some countries, the hair is, Plastic Bins or has been subject to censorship , so in Japan in the years 1960 to 1990, is the vision of the hair more than the nudity was banned in the movies or manga (comic books). [ref. requi