Everything about hair

It seems ridiculous to say that the beauty of a woman’s hair depends in part on her culture. But among women dissatisfied with the appearance of their hair, 90% make flagrant mistakes in the care they give to their hair; or, worse, it does not give the hair any care. This is because they do not have enough knowledge about hair.

We will therefore begin this series of articles, with a chapter that summarizes the basics of the anatomy of the scalp and hair, possible hair diseases and their causes, means of prevention or cure, etc.

The scalp

Like the skin on the body, the scalp consists of three overlapping layers:

• epidermis,
• derma,
• and a greasy surface called the hypodermis.

Epidermis

The epidermis consists of six layers, of which the first (from the inside to the outside) is the germinal one. This is where the process of cell multiplication takes place. Also here is melanin, the pigment that colors the skin. The biological activity of the germ layer is very important: the healthy and young appearance of the skin depends on it.

The second layer is the filamentous one. The cells that form it are connected to each other by filaments through which the nutritive plasma of the epidermis circulates.

The third layer is the granular layer in which granules of a substance called keratosin can be seen, with a role in the development of epidermal fat.

The transition zone between the granular and the stratum corneum is the lucid layer, where the degenerate substances are soaked by a substance called keratin. In this layer begins the aging process of the cells.

In the stratum corneum, the cells are arranged like roof tiles and are soaked with soft keratin (unlike hard keratin – nail and hair). This layer is poor in water, but is soaked in a fatty substance that gives it suppleness, and prevents evaporation from the inside out, and the penetration of liquids from the outside to the inside. It has a protective role.

The sixth layer is the disjunctive layer and is composed of keratinized cells that peel off the skin and fall off.

The dermis

The dermis is much thicker than the epidermis. It consists of cells, fibers, blood vessels, which nourish the dermis and epidermis with nutrients provided by the blood, and nerves, some with a sensory role, others with the role of regulating the functioning of blood vessels.

 

Skin appendages – hair and glands

Glands

There are two types of glands in the skin:

• sweat glands – which secrete sweat and are not abundant in the head region;
• sebaceous glands – which constantly secrete a fat called sebum. They are attached to the hairs, and their size depends on the size of the hair. At the level of the scalp, they are very abundant and voluminous. Sebum plays a role in lubricating the hair. It not only gives the hair shine, but also increases its impermeability, preventing it from dehydrating. Shallow than sweaty thoughts, they are located in the middle portion of the dermis and are attached laterally to the hair follicle, where they open.

Located obliquely under the sebaceous gland, there is an erector muscle, which contracts independently of our will under the influence of various stimulus such as cold or fear. It acts as a lever, lifting the hair which normally has an oblique insertion in scalp. When your hair is scared, this muscle is to blame.

The hair

The hair covers the human body almost entirely, except for the palms, soles and navel. The hair consists of a root, implanted obliquely in an extremely small cavity of the skin, called the hair follicle, and a stem, which represents the visible part, outside the skin.

At the lower end of the root there is the hair bulb, which is the seat of life and hair growth. Its base is in the shape of a nest. At the top is a type of connective bud called the hairy papilla, which contains numerous blood vessels and nerves.

The type of hair differs from one area of the body to another, according to the size, thickness and depth of implantation in the dermis. The scalp is an area where the hair follicles are extremely abundant, very deep and produce thick and particularly long hairs.

Hair structure

Regarding the cellular structure of the hair, the essential differences are between the hair bulb and the hair itself (root + stem).

The bulb is made of living, young cells, nourished in abundance by the blood vessels in the hairy papilla, which I mentioned above. The bulb is the area of hair growth.

At the top of the bulb and between the cells that will form the thread itself above, there are some large cells, with multiple extensions, loaded with pigment granules. These cells make the pigment of the whole thread.

The hair itself starts from where the bulb loses its specific shape, turning into a tube consisting of three concentric layers:

1. On the outside is a corneous layer called the cuticle (5% of the diameter of the hair). It consists of keratinized cells (loaded with keratin. Keratin is a water-rich, sulfur-rich scleroprotein), stacked on top of each other like scales with a protective role.
2. Next comes the cortical layer, called the cortex, which is made up of spindle-shaped, keratinized, dead cells. Some of the cells contain pigment. This layer represents 75% of the diameter of the hair.
3. The marrow is a soft, fat cylinder containing round cells. It also contains pigmented granules, and sometimes tiny air bubbles. The marrow represents 20% of the diameter of the hair.

Physical properties of hair

Normal hair is:

• solid: a hair can hold weights vary between 40-160 g, depending on the breed to which it belongs (the hair belonging to the yellow breed is the strongest, the negroid weaker than the European one);
• elastic and flexible;
• hygrometric – elongates under the influence of humidity;
• porous.

How hair grows

As you have already learned, hair grows at the level of the cell multiplication area in the bulb. the young cells push out the old ones. so the hair grows from the bottom up.

Hair grows at a rate of about one centimeter per month. The intensity varies from subject to subject, it is more accentuated between 20-30 years, and faster in summer than in winter. As the hair grows from the bottom up, anatomically and physiologically, cutting the extremities has not been shown to accelerate its growth. The only explanation would be that short hair is easier to care for.

The hair grows for about 3-5 years, the average length reaching up to 85 cm. However, there are women who have a hair of 1 -1.5 m. After years of growth, the hair enters a resting phase, dies and falls out.

How hair dies

The hair dies when the bulb separates from the papilla that nourishes it by interposing a thick membrane. The bulb rises to the surface and the thread will be removed in about 70 days. A new bulb will form associated with the remaining papilla.

Hair curling

This phenomenon of hair curling is due to keratin. As seen, keratin is found in straight, loose hair, but can bend under the influence of water, heat and pressure. This is the principle of ripples with water or iron. From a chemical point of view, keratin remains unchanged, the difference being only the physical condition. But certain chemicals, such as thiogglycolic acid, can break the bonds between the ear chains that form keratin, which makes hair very malleable. Ties can be formed elsewhere, allowing the threads to take on a new shape. It is the principle of perms, which attacks the structure of leratin in order to curl hair.

Hair color

Hair color is due to a natural pigment called melanin. The pigmented cells are located in the bulb and have extensions to the cortex.

Melanin exists in hair in two associated forms:

• diffuse: in yellow plaques;
• contoured: brown granules.

The color depends on the proportion of one of the shapes in relation to the other. Thus, blond hair contains melanin in diffuse form and black hair in the form of granules. Chemically, the melanin of red hair is slightly different from that contained in the other colors.

Melanin granules are attacked and discolored by various oxidants, such as hydrogen peroxide. The sun’s rays also act in this direction. The bleaches attack the brown granules and leave the diffuse melanin intact. The result is that bleached hair acquires a characteristic color: straw yellow. The basic shade determined by melanin can be modified by two accessory factors:

• the inclination of the epidermal cells, which will reflect more or less light after their placement;
• the amount of air bubbles present between the cortical cells: the more there are, the lighter the hair looks.

Why bleach your hair

With age, the number of pigment cells decreases and air bubbles multiply. These would be the reasons for this phenomenon, which is related to other factors.

The rapid whitening, caused in a few hours, or a few days, has only recently found an explanation. It is attributed to a ferment that would be born in the blood, to emotional shocks and would be able to quickly discolor melanin in the hair, thanks to its remarkable diffusion properties.

Oily, dry or normal hair?

Here is a precise way to determine:

Three days after washing your hair, rub the scalp for 30 seconds with your index finger. Then apply your finger to a sheet of cigarette:

• hair is greasy if the finger leaves a visible, very oily mark on the paper;
• the hair is dry if the trace is very light, almost non-existent;
• hair is normal if the mark left on the paper is similar to that left by sweaty fingers during the summer.

Why does hair fall out?

The daily fall of a few hairs is normal (up to 30-40 hair wire). These are being replaced by others that are growing. Hair loss becomes a concern when the number of hairs that fall out daily exceeds 100. Hair loss can be caused by several causes:

1. seborrhea (excess fat);
2. poor general condition, digestive disorders;
3. treatment with male hormones, which can cause hair loss on the head and abnormal growth of hair on the body and face;
4. abuse of certain shampoos too detergent;
5. a sudden weight loss cure. Hair can fall out even six months after the start of the treatment;
6. brutalization of hair at the taping;
7. brutal brushing, with plastic brush;
8. discoloration too strong;
9. hairspray abuse (it is recommended to use hairspray at most 2-3 times a week);
10. permanently with too concentrated solution;
11. wrong or insufficient diet – an unbalanced menu;
12. non-compliance with the mandatory rules of hair hygiene;
13. non-aeration of hair (tightening in a scarf or basque for a long time);
14. after surgery, infectious disease, intoxication, menopause, after pregnancy.

The fall is temporary and in most cases, the situation returns to normal. The cause of hair loss must be determined by your doctor. It will also indicate the necessary treatment.

In the next article you will find out the current conditions of the scalp as well as a series of remedies that will help you maintain the health and beauty of your hair.