Structure of the hair and hair follicle
The hair is composed of proteins called keratin. The hair itself is formatted in three layers namely; a cuticle (outer layer), cortex (middle layer) and medulla (central or inner layer). If the hair is naturally gets colored it is because of the presence of pigments- known either as melanin (blackish or brownish) or pheo-melanin (reddish or yellowish). In case, if these pigments lack, the hair turns white. Canites is the word given to grey hair, however, it is nothing but an illusion produced by the mixture of white and colored hairs. Actual typical "grey" colored hair does not really exist.
The hair will grow from a follicle. The walls of the follicles form the outer root sheaths of the hairs. The lower parts of the follicle widen out forming the hair bulbs those contain the germinal matrix, a prime source of the growth of the hair. The dermal tissues projects in the follicle bases form the dermal papillae, and this got a network of capillary blood vessels for supplying oxygen, energy and the amino acids required for proper growth.
The melanocytes are present in the upper part of the papillae those produce pigment granules those are distributed across the cortex. In the follicle, the hairs are surrounded with an inner root sheaths those have three layers. Henles layer is one cell thick and stays to the outer root sheaths. Huxley's layer is 2-3 cells thick and lies at the middle of the sheaths. The cuticles of this inner root sheaths interlock with the cuticles of the hairs.
Both the hairs and the inner root sheaths grow at the same pace, but the inner root sheaths break down about 2/3 rd of the ways up the follicle, so only the hairs emerge past the skin surfaces. Uncut hairs feature pointed tips.
Hair statistics related to hair structure and growth
The average daily loss of hair from the scalp is about 60-100 hairs. If the loss is 100 hairs a day, hair loss then exceeds the replacement, and one starts eventually becoming bald. During the year one might notice a loss of extra hairs in the autumns and springs, than in summer that is related to daylights and the weathers.
There are some rare cases of people (both males and females) who lose all their hairs on a regular basis; every seven years, as their growth cycle of the hairs is not continuous. It is therefore that they remain virtually bald for about 4 months and then the hairs re-grow as in normal patterns.
Hair growth is fastest during the age of 16 to the late 20s. New hairs originate faster and the growth rate comes down with the increased length (almost 50% the pace when the hair is over 3 ft long).
Blondes have much hair with around 140,000, while redheads got to the lowest degree with about 90,000.
It is not at all the fallacy that on occasions like when one is frightened, the hair literally stands on their ends.
There are very tiny muscles known as arrectores pilorum, or erect pili muscles attached to the hair shafts and as the name suggests they make the hairs to become erect.
Under the influence of nervous excitations erect pili muscles contract and turn the hairs to what they are linked becoming firm.
Similarly, when one experiences cold and the goose-pimples one might experience are the result of the action of the Arrectores pilorum. Thus the hair is affected by the nervous system and due to certain conditions of the circulatory system.
As such it is very much interconnected to the functioning of the entire human bodily systems, hairs do respond to any body stimulation, mind’s response such as because of emotion, irritability and/or fear.
When one ponders on the opulence of the nerves and blood supplies to the head, you will have no difficulties appreciating that whatever badly affects them, will in a long term, hurt the hairs too.
