Myself as An Individual: The Hair

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Welcome to class! 

In today’s class, we will be talking about myself as an individual: the hair. Enjoy the class!

Myself as An Individual: The Hair

Hair is simple in structure but has important functions in social functioning. Hair is made of a tough protein called keratin. A hair follicle anchors each hair into the skin. The hair bulb forms the base of the hair follicle. In the hair bulb, living cells divide and grow to build the hair shaft.

Hair growth occurs in cycles consisting of three phases:

• Anagen (growth phase): Most hair is growing at any given time. Each hair spends several years in this phase.
• Catagen (transitional phase): Over a few weeks, hair growth slows and the hair follicle shrinks.
• Telogen (resting phase): Over months, hair growth stops and the old hair detaches from the hair follicle. A new hair begins the growth phase, pushing the old hair out. 

Hair grows at different rates in different people; the average rate is around one-half inch per month. Hair colour is created by pigment cells producing melanin in the hair follicle. With ageing, pigment cells die, and hair turns grey.

Types of hair

• Oily hair
•  Dry hair
•  Normal hair

• The root of the hair:

The root of the hair ends in an enlargement, the hair bulb, which is whiter in colour and softer in texture than the shaft, and is lodged in a funicular 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 and granular stratum, cuticle, cortex and medulla.

• Natural colour:

A woman with dark blonde hair, the basal colour appears brown due to higher levels of brownish eumelanin. All-natural hair colours 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 fibres. 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. Grey hair occurs when melanin production decreases or stops, while polyposis 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 globules 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 while one strand of hair may be in the anagen phase, another may be in the telogen phase. 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 type of cellular construction. The different construction gives the hair unique characteristics, serving specific purposes, mainly, warmth and protection.

• Texture:

Hair exists in a variety of textures. Three main aspects of hair texture are the curl pattern, volume, and consistency. The derivations of hair texture are not fully understood. All mammalian hair is composed of keratin, so the make-up of hair follicle is not the source of varying hair patterns. There is a range of theories about the curl patterns of hair. Scientists have come to believe that the shape of the hair shaft affects the curliness of the individual’s hair. A very round shaft allows for fewer disulphide bonds to be present in the hair strand. This means the bonds present are directly in line with one another, resulting in straight hair.

 

In our next class, we will be talking about the Eye.  We hope you enjoyed the class.

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