Why do we care about hair | Naomi Abigail | TEDxBaDinh

Hair:

Is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles that produce thick terminal and fine vellus hair. A most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin.

Attitudes towards different forms of hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, sex, or religion.

The word "hair" usually refers to two distinct structures:

1- the part beneath the skin, called the hair follicle, or, when pulled from the skin, the bulb or root. This organ is located in the dermis and maintains stem cells, which not only re-grow the hair after it falls out but also are recruited to regrow skin after a wound.

2- the shaft, which is the hard filamentous part that extends above the skin surface. A cross-section of the hair shaft may be divided roughly into three zones.

Hair fibers have a structure consisting of several layers, starting from the outside:

1- the cuticle, which consists of several layers of flat, thin cells laid out overlapping one another as roof shingles.

2- the cortex, which contains the keratin bundles in cell structures that remain roughly rod-like.

3- the medulla, a disorganized and open area at the fiber's center.

The root of the hair

Ends in an enlargement, the hair bulb, which is whiter in color and softer in texture than the shaft, and is lodged in a follicular involution of the epidermis called the hair follicle. The bulb of hair consists of fibrous connective tissue, glassy membrane, external root sheath, internal root sheath composed of epithelium stratum (Henle's layer), and granular stratum (Huxley's layer), cuticle, cortex, and medulla.

Natural color

A woman with dark blonde hair. The basal color appears brown due to higher levels of brownish eumelanin.

All-natural hair colors are the result of two types of hair pigments. Both of these pigments are melanin types, produced inside the hair follicle and packed into granules found in the fibers. Eumelanin is the dominant pigment in brown hair and black hair, while pheomelanin is dominant in red hair. Blond hair is the result of having little pigmentation in the hair strand. Gray hair occurs when melanin production decreases or stops, while poliosis is hair (and often the skin to which the hair is attached), typically in spots, that never possessed melanin at all in the first place, or ceased for natural genetic reasons, generally, in the first years of life.

Human hair growth

Hair grows everywhere on the external body except for mucus membranes and glabrous skin, such as that found on the palms of the hands, soles of the feet, and lips.

Hair follows a specific growth cycle with three distinct and concurrent phases: anagen, catagen, and telogen phases; all three occur simultaneously throughout the body. Each has specific characteristics that determine the length of the hair.

The body has different types of hair, including vellus hair and androgenic hair, each with its own type of cellular construction. The different construction gives the hair unique characteristics, serving specific purposes, mainly, warmth and protection.

This 10-second Monk Ritual Supports Healthy Hair Growth