Hairs are hairy ends that grow on the scalp and are common hairs .
Hair always falls into the category of terminal hairs, as hairs are divided into different types.
Vellus hair
Vellus hairs are small and almost invisible, similar to fluff and distributed over almost all human skin, including the scalp.
These hairs are rooted in small follicles, but have large sebaceous glands;
Terminal hairs
Terminal hairs are thicker, longer, and more pigmented (colored), and are located on the scalp and other areas of the skin, such as the limbs, pubis, armpits, and, for men, the face.
These hairs sink into larger follicles than vellus hairs, but with smaller sebaceous glands.
Since the hair is a common hair, like all hairs, it develops from the hair follicle.
The latter is housed in the subcutaneous tissue (hypodermis), and this is why the distance between the point of emergence of the hair on the skin and the follicle can reach one centimetre.
The sebaceous gland, on the other hand, is grafted into the hair follicle at the level of the dermis, therefore it is located close to the epidermis and the surface of the scalp .
The union of the hair follicle with the sebaceous gland gives rise to the pilosebaceous apparatus .
Healthy hair
Healthy and naturally developed hair consists of three parts:shaft (or stem) of the hair
The hair shaft or stem is the part outside the follicle, visible on the scalp, with an average thickness of 65-78 microns in adults.
It is the dead part of the hair, formed by totally keratinized cells which have lost their vital functions, but have acquired resistance thanks to the high concentration of an extraordinarily resistant fibrous protein, Keratin;
Root
The root is the part inside the follicle and is not visible because it is immersed in the scalp of the hair until it reaches the dermis.
It is the living part of the hair, which ensures its growth and renewal;
Hair bulb
The hair bulb is positioned even deeper than the root, in the lower portion of the hair follicle, where the dermal papilla is inserted, rich in nerve endings and blood vessels responsible for nourishing the hair.
The dermal papilla gives rise to a matrix of germinal cells which, by reproducing, push those previously created upwards.
It is during the ascent of the cells towards the skin that the keratinization process takes place which stiffens the hair, devitalizing it and giving rise to the shaft.
Consequently, in contrast to what is commonly thought, to strengthen the hair it is useless to cut it short or shave it, since, in this way, the stem is only being amputated, that is the already dead part of the hair.
The hair cut therefore has no effect on the increase in hair keratin levels, it does not serve to strengthen the hair, but to avoid weakening it.
The only real positive effect of cutting short hair therefore consists in the reduction of traumas from washing, combing and brushing, therefore of all those practices that can weaken them.
Healthy hair shaft
By sectioning a hair horizontally, you can identify the three layers that make up its structure:
Cuticle
It is the outermost layer, formed by transparent and thin cells (thickness 0.2/0.5 microns).
The cuticle protects the integrity of the hair, but being exposed to the outside it is the first to be damaged by environmental agents.
Excessive exposure to aggressive substances, inadequate shampoos, perms, continuous brushing, to name a few, tend to damage the cuticle, endangering the health of the hair .
Bark
It is located below the cuticle and forms the thickest layer of the hair (shaft), determining its shape and texture.
A bundle of macrofibrils, arranged vertically in parallel rows, contain colored pigments, melanin, which gives color to the hair.
These pigments decrease in number with age, giving rise to the process of graying, by which the hair turns white.
When we use products to change the color of the hair or to bleach it, when we oxygenate it or use perms, shampoos or alkaline hair cleansers, the hair undergoes chemical changes at the level of the cortex (cortical alterations), and this is where the color change takes place , given that the cuticle, the outermost layer without melanin, is transparent by nature.
At this point, if the hair were examined (hair check-up) with a microscope at high magnification, it would show evident damage on the whole structure and in particular at the level of the cuticle.
Hair taken from any point of the scalp could easily be completely devoid of cuticle, which has disappeared under the effect of harmful chemical agents.
For example, the problem of split ends (trichoptilosis), i.e. the longitudinal fissure of the hair shaft, is often caused by repeated combing of hair that has already lost its cuticle following inappropriate physical-chemical treatments.
In these cases , protecting the health of the hair first of all means avoiding weakening it and risking losing it.
Problems of split ends and brittle hair are quite common and make the hair already categorized as unhealthy , which is why it is necessary to intervene with trichological treatments aimed at strengthening the hair both at the cuticular and cortical level.
Therefore intervening quickly with the right product and the right trichological treatment allows you to return to having healthy and strong hair .