There are hundreds of interesting facts about hair, and we don’t even know most of them. Some of them have no meaning, when it comes to hair care, while others play an important role in it. Let’s get to know the secrets and 10 more curiosities about the hair anatomy.

Occurrence of hair

Hair is a product of the epidermis, that occurs on the entire surface of the skin, except the inside of the hand, soles of the feet, and joint bends. Hair grows from a skin cavity, called the hair follicle. Today, hair has mainly an aesthetic function. The hair follicle is made out of the outer connective and internal epithelial parts. These two layers are separated by a thin basement membrane, that remains in the hair follicle. The speed of hair growth depends on age, sex and individual conditions. Hair grows in average one centimetre per month.

Hair structure

Hair consists of three basic layers. The first is the outer layer, taking the form of a thin casing. The second is the middle layer, i.e. the hair bark. The third and inner layer is the core. Each well-developed hair has a root, which is placed in the hair follicle. The most important part of the root is the matrix, which contains live hair cells. This is the place, where intensive metabolic processes take place. There is a division, that leads to pushing out old cells. The area with the old cells, is replaced by new ones, which will also be dying after some time. The visible part of the hair is a shaft, which is made out of dead cells. The inside of the hair is keratin, a protein rich in sulfur.

The cycle of hair development

Hair growth occurs in the hair papilla and is characterized by 3 phases. The hair growth cycle is repeated over and over again, while the order of the phases is always the same. Cycles in neighbouring bellows are shifted in time, due to which hair appears regularly. There are 3 phases of hair growth:

  • anagen, i.e. the active phase of hair growth in the bellows. The matrix makes an intense division. The duration of this phase is genetically determined and can last from 2 to even 7 years. On a healthy scalp, 90% of the hair should be in the growth phase.
  • catagen, i.e. the disappearance phase. This is an extremely short phase that lasts from 14 to 21 days. After that, hair remodelling processes take place inside of the hair root. The hair matrix disappears, and the hair is pushed towards the skin’s surface. About 3% of the hair on the head is in this phase.
  • telogen, i.e. the phase of prolapse. The hair is already completely calloused and there are no processes taking place in it. The phase lasts from 30 to 90 days, and its final stage is hair loss. About 13% of the hair is in this phase.

What is the maximum amount of hair on the head?

Humans are born with a certain number of hair follicles. Blondes usually have the most bellows, while people with red hair have the least. Brunettes occupy the middle position in this ranking. The average amount of hair on a person’s head is 100-150 thousand. Their density per 1 cm2 ranges from 150 to 750 hairs.

Are diseases the only cause for hair loss?

Hair loss acceleration can have many different causes. These include thyroid problems, cancer, anaemia, and infections. Hair loss can also be caused by mineral deficiencies or hormonal changes, which can occur during pregnancy or menopause. Alopecia can be caused by an inadequate diet, slimming, stress or poor care.

Where does the hair colour come from?

The hair colour results from the pigment that is melanin. If melanin takes a dispersed form, then the hair has a light colour. Melanin proportions can create up to 50 hair colours.

hair color

hair color

Can a hair support more than its weight?

A huge curiosity about hair is their durability. Healthy, thick hair can withstand a load of up to 250 grams. The hair, on the other hand, weighs 1/1000 grams. Hair durability is associated with chemical and biological factors.

Function of hair

Nowadays, humans treat hair as an ornament. Hair in his natural form, has a thermoregulatory and protective function. Nowadays, people have limited these functions.

What is the professional term for hair science?

The field of medicine, dealing with the diagnosis and treatment of hair-related problems, is called trichology. Its name comes from the Greek word “trikhos” (hair) and “logos” (science). A trichologist examines the causes of hair loss or weakness and initiates an appropriate treatment.

Is every hair build the same way?

Every hair is built from the stem and root, located in the hair follicle. An interesting fact is, that depending on the type of hair, they have a different shape in cross-section. Straight hair has a round cross section, wavy takes the form of an ellipse, and curly is characterized by a flattened oval.

Is hair alive?

The only part of hair, that is alive, is the hair root. This is where all the processes, which stimulate hair growth, take place. The rest of the hair is dead and is formed by calloused keratin cells.

Genetics cause red hair

Only 4% of the world’s population has red hair naturally. The information about hair colour is genetically recorded and passed on by the parents. Interestingly, neither one of the parents need to have red hair. The red hair gene is dormant in many people, because it loses with other colours. People with red hair don’t get grey hair as fast as other hair colours.

The amount of hair all over the human body

There may be as many as 5 million hair follicles in a person. Their quantity is recorded in genes and is shaped at the stage of fetal life. Each hair follicle will produce 20-30 strands throughout its life.

There are many interesting facts about hair. Each hair contains a lot of information, that is transmitted genetically. Daily care has a huge impact on the condition and state of the hair. It is also worth paying attention to a healthy diet and lifestyle.

 

Last update: 19 October 2020

Dr Piotr Turkowski

About Dr Piotr Turkowski

Aesthetic medicine doctor, specialist and enthusiastic surgery, completing the specialization in plastic surgery. The only officially registered member of the international hair restoration surgery (ISHRS) in Warsaw, which brings together the world's best specialists in this field.

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