Introduction

Since antiquity hair is synonym to strength. Already in the Greek mythology hair played an important role. Samson, a Greek hero, drew its strength from its hairs. Nowadays hair plays a very important role. Not only social, but also psychological. With a hairstyle one can distinguish oneself of the rest of the society, for example skinheads and rappers. But also in more officially ranks, like in the English courtrooms, a certain form of uniformity is reached by means of wigs. Sentences such as “money is power, hair is strength” and “as long as your haircut is beautiful” confirm once again the importance of hair. The interaction between persons becomes strongly influenced by the hairstyle. The hairstyle must correspond with the personality and with the self-image of a person.

Explanation

From research it becomes clear that from the whole body, hair has the most attention. When one is observing someone, the hairstyle is observed first. Of course one will not assess each other to the hairstyle, but it is influencing the first impression. From research it also becomes clear that people with much hair are found nicer, rather are helped and are valued more young. Therefore hair is very important for social and psychologically functions. So it is not astonishing that persons, both men and especially women, who suffer from a hair-problem, are damaged in their self-confidence. From experience we know that mental and physical complaints can result from hair-problems. Psychosocial acceptance of the self-image is therefore influenced by the hairstyle. Therefore one must take a person with a hair-problem seriously and don’t treat them incorrectly.

Recommendations

There exist agencies which give recommendation in the total self-image and self-esteem of a person. Many people with hair-problems don’t dare to make the step to the hairdresser anymore, it is advisable that a person with a hair-problem talks with a doctor, concerning the possibilities and impossibilities with their hair.

Anatomy & Physiology

The usual classification of hair-types is:

– laguno-hair:     long, silky hair without pigment, that usually is ricocheted in the uterus, but sometimes is still present on the skin of new-born.

 

Fig. Comparison of vellus and terminal hair

 

– vellus-hair:      thin, briefly hair without pigment.

 

– terminal hair:   thick, stiffly hair, of several length, generally pigmentation.

 

 

Beside above classification, there are three different types of terminal hair on the body:

 

1: Growth is independent of male hormones.

Examples:   – Back of the head skin

– Eyebrows

– Lashes

– Nose hair

– Ear hair

 

2: Growth depends on the male hormone testosterone, and to a lesser degree on the male hormone      

Dihydrotestosterone.

Examples:         – armpit hair

                        – pubic hair

 

3: Growth depends on the male hormone Dihydrotestosterone, and to a lesser degree on the male hormone testosterone.

Examples:         – barb region.

– Hair on the limbs.

– chest hair and hair on the back.

 

 

 

 

The normal compactness of hair amounts at babies to ± 1000 hair by square centimetre, to 250 hair  at people around 50 year. The total number hair on the head skin varies between 90,000 and 150,000 hair.

This differs by hair colour.

– Blond hair:      ±150.000 hair

– Brown hair:     ±110.000 hair

– Black hair:       ±100.000 hair

– Red hair:         ± 90,000  hair

 

The structure of the hair can to be subdivided in several structures (from the inside out):

* Medulla:                           Marrow (both in internal and external hair present)

* Cortex:                             fibre layer (both in internal and external hair present)

* Cuticula:                           scale layer (both in internal and external hair present)

* Inner root sheath:              Inmost root of a hair sheath (only in the internal hair present, part of hair follicle)

* Outer root sheath:             Outmost root of a hair sheath (only in the internal hair present, part of hair follicle)

* Bulge-area:                       Part of the outmost root of a hair sheath, off the sebaceous gland. (only in the internal hair present, part of hair follicle)

* Dermal papilla:                  Hair papilla, with two capillary vessel (only to the base of the internal hair presently, part of hair follicle)

 

Fig. Cross-section of a hair follicle

 

 

The bottom part of the picked hair,  also called hair bulb or hair knob.

Furthermore there are the so-called hair-annexe (= appendices) such as the hair muscle and sebaceous gland. The hair muscle ensure that under certain circumstances such as coldness, the hair remains intact. The consequence is goose-flesh. The sebaceous gland are responsible for the grease-content of the hair and the skin.

With composition of the hair we mean the composition of the different substances in the hair. Hair exists from endosperms (±85%), water (±12%), greases (±3%) and trace elements (±1%) such as Zinc, lead, purchaser and selenium. When the hair is laid in water, the percentage can double,. Furthermore the percentage of water is depending on the air humidity degree, grease and hair structure.

Fig. haircycle

 

Hair has a cycle,  which exists from three phases. The first phase is the anagen or growing phase. This phase can vary from a month (eyebrows) up to 12 years (head skin), depending on  the location. The difference in life span explains directly the difference in length in the different areas on the body (to see diagram). Afterwards the katagen or passage phase follows. The hair is no longer growing at this stage and it starts to die. Finally it ends up in telogen or rests phase. This phase lasts approximately 3 to 6 months. Because this phase lasts so long as, it can explain why the hair loss takes place just 3 to 6 months after something happens.

 

 

Rate of growth

 

Depending on the location, hair grows average of 0.1 mm/day (body hair) up to 1mm/day (barb region). Between the different individuals however large differences can exist. This is caused by the genetic properties of the individual.

 

 

Types hair, hair cycle, life span

 

 

 

 

 

Anagen

 

Katagen

 

Telogen

 

Rate of growth

 

Maximum length

 

 

 

 

Type 1

 

 

 

 

Skin of the head

 

10-12

years

 

 

 

3-6

Months

 

0,44 mm./day

 

100-120 cm.

 

 

Eyebrows

 

3-6

months

 

 

 

3-6

Months

 

0,1 mm./day

 

1,0-2,0 cm.

 

 

Lashes

 

1-2

months.

 

 

 

3-6

Months

 

0,1 mm./day

 

0,5-1,0 cm.

 

 

Nose hair

 

1-2

months

 

 

 

3-6

months

 

0,1 mm./day

 

0,5-1,0 cm.

 

 

Ear hair

 

1-2

Months

 

 

 

3-6

Months

 

0,1 mm./day

 

0,5-1,0 cm.

 

 

Type 2

 

Armpit hair

 

1-2

years

 

 

 

3-6

months.

 

0,3 mm./day

 

4,0-6,0 cm.

 

 

Pubic hair

 

1-2

years

 

 

 

3-6

Months

 

0,3 mm./day

 

6,0-8,0 cm.

 

 

Type 3

 

Barb region

 

6-12

months

 

 

 

3-6

Months

 

1,0 mm./day

 

75-100 cm.

 

 

Hair on the limbs

 

1-2

months.

 

 

 

3-6

months

 

0,44 mm./day

 

2,0-3,0 cm.

The colour of the hair is stipulated by the cells producing pigment. There exist three types of pigment:       * Eumelanine = blond/light brown/dark brown

* Phaeomelanine = red/purchaser gold/ auburn

* Trichosiderine = containing iron pigment substance and is red.

 

The composition and production of the different types pigment depend on the genetic properties, resulting in different hair colours, which can vary of white/high blond to dark black. During life it’s possible that the production and composition of pigment varies, resulting in a chance that one has high blond hair during childhood, at a higher age dark brown , afterwards grey and later white hair.

The skin between the hair follicle and the surface of the skin is stipulating the form of the hair (steep, wavy or curly). When in this piece the hair root canals are bent, this can result in wavy or curly hair. In certain periods such as childhood and puberty, it’s possible that flexibility and stiffness of the head skin differs with other life periods. Because of this it can occur that during childhood one has wavy hair, during puberty style hair and during adulthood style hair again.

Hair elasticity is probably the most important mechanical property of the hair. After strengths have been released, such as pull strengths, bend strengths, compression strengths and torsion strengths, on the hair, it’s possible to return back in its original form, volume and length. This happens because of the elasticity of hair. With pull strengths one means “strengths resulting in an increased the length of the hair”. With bend strengths one means “strengths which bend the hair”. With compression strengths one means “strengths where the hair is pressed “. With torsion strengths one means “strengths where the hair is twisted”. Each strength has its own formula define strengths. However, the examined strength is the pull strength of the hair.

The most used formula for this is the formula according to Young:

 

FL

—- dynes by unit area

al

 

F = strength by Unit area of a certain distance.

a = Unit area of a certain distance.

L = length of the hair before drawing.

l = length of the hair after drawing.

 

With this formula can be calculated how much strength is necessary to pull off a hair a certain distance.

Of course strength which can be exercised on the hair, so that it returns in the original state is limited. At normally dry hair, the hair can be tear approximately 30% and return entirely in the original length. Between ±30% and 70% it won’t break, but it will no longer return in the original length and the hair will be longer than therefore. When the hair is teared more than 80%, it will break.

The elasticity of the hair depends of the humidity of the hair. How wetter the hair is , how more elastic it will be. Also the thickness of the hair can influence the elasticity of the hair. How thinner the hair, the more elastically the hair is.

Hair treatment such as paintings, bleaches and perm can reduce the elasticity from the hair up to 25%. Also sunlight can influence the elasticity of the hair negatively.

 

Brilliance of the hair is stipulated by the degree of grease of the outer root sheath of the hair. When outer root sheath is damaged, for example by having a perm,  the cuticula or scale layer is damaged, and the hair can lose its brilliance

Hormones

Different processes

Female hormones

Male hormones

General information about male hormones