Human Hair: Interesting Facts, Functions, and Composition

Facts about human hair, its role or function, the details of natural hair loss, its growth and its color all make very interesting reading.

Every part of your body is fascinating by itself. And, so is your hair!

For example, your heart beats about 72 times per minute, 24×7, for all the years that you live and it does so by generating its own electricity.

Your lungs expand and contract 16 times a minute for all the years that you live.

Your veins continuously carry blood from the lower parts of the body upwards to your heart against gravity.

Ever wondered how all this happens and that too with coordination? Your hair, too, is an interesting part of your body and these statistics about it make interesting reading about some unknown facts.

Besides,

  • Know of what element your hair is made up of.
  • What is its chemical composition?
  • What are its functions at different parts of the body?
  • Is your hair dead or alive?
  • What is its anatomy and structure?
  • From where does your it originate?

About Human Hair

You have it all over your body and not just where you see it (e.g., on your scalp, pubic region, hands and the legs).

You do not see it on certain parts of the body though it is present. The hair on the face, forehead, and the cheeks, though present is invisible, but it is there.

However, you do not have it on your lips, palms of your hands and the soles of your feet. It is totally absent on these parts.

Functions of hair

The hair on each part of your body has different functions perform. For example,

  • It protects the scalp from the heat and the ultraviolet radiation from the sun and keeps your scalp warm during the cold.
  • The eyebrows protect the eyes from the sweat coming down from your forehead.
  • The eyelashes protect the eyes from the dust and filter off extra light.
  • In the nostrils and the ear, it prevents foreign particles such as dust and insects from entering.
  • The hair on the body is connected to the sensory nerve endings (touch receptors) in the skin and helps you feel the breeze and any foreign object making you aware of its presence.
  • The function of the pubic hair and that in the armpits is to act as a cushion against the friction of skin rubbing against skin and preventing any abrasion and subsequent infection.

Facts About Human Hair

  • Its life cycle is about 2 to 7 years. You can describe the cycle in three words: — rest, shed and grow.
  • Ninety percent of it is in a growing phase at any given time and 10% is in the resting phase.
  • That, which is in the resting phase falls off within 2 to 3 months and new hair begins to grow in its place.
  • It grows at the rate of about one centimeter per month, faster in summer than in winter.
  • It grows at the rate of 0.3 to 0.5 millimeters per day.
  • Normally, you do shed it every day. You lose about 50 to 100 hairs every day. However, when this loss becomes excessive, you should take precautionary and preventive steps.
  • There are 100,000 to 150,000 hairs on a normal scalp.
  • The diameter of human hair is 0.1 mm
  • It can tell if you smoke, drink, or take drugs, but it cannot tell your gender.
  • A single hair strand can support about 100 grams weight.
  • Asian hair grows the fastest.
  • Africans and Europeans are more prone to baldness than the Asians are.
  • Hair color and its statistics:  Black/Brown-haired people have 25% more growth than red-haired people while the blond people have 25% more growth than black/brown-haired people.
  • It is the fastest growing tissue in the human body after the bone marrow

According to women’s hair restoration expert Lucinda Ellery, and as mentioned in the Huffington post :

“By the time you’re 15, it’s the best head of hair you’ll have for your entire life. By the time you’re 30 there will be a significant change in your hair, but not one you may have clicked into mentally. By the time you’re 37, 40, there’s a marked changed. This is where people panic — it’s a natural cycle of aging.”

What is human hair made up of? Chemical composition

Keratin

Human hair is made up of a type of protein called keratin, a fibrous protein, which is formed from amino acids. It is the same protein, which is present in fingernails, toenails, teeth and the skin.

Keratin is an insoluble protein made from eighteen amino acids, of which cysteine is the most abundant.

Amino acids

Amino acids, which are the building blocks of protein are made up of 45.2 % carbon, 27.9% oxygen, 6.6% hydrogen, 15.1% nitrogen and 5.2a% sulfur.

The amino acid, cysteine disulfide, makes sulfur atoms to form disulfide bridges and it is the combination of the amino acids and disulfide bridges, which determines the type of hair you will have.

Melanin – your hair pigment

Besides keratin, amino acids and protein, there is another element present in hair. It is called melanin, which is made from melanocytes. Melanocytes are specialized cells, which are present near the hair bulb.

It is the melanin, which gives your hair its color. Depending on the type of melanin you have inherited, it may be black, brown, red or blond.

In terms of structure and the growth cycle, it is identical in men and women.

Structure of the hair shaft: Anatomy

The anatomy of the hair shaft is made up of three layers:

  1. Medulla is the innermost layer and is present only in thick hair.
  2. Cortex, which is the middle layer, provides color, texture,and strength to the hair.
  3. Cuticle, which is the outermost layer is thin, colorless, and provides protection to the cortex.

From where does hair grow? About its follicle and root

The root of the hair is situated within its follicle below the surface of the skin. It is the follicle, which plays a vital role and anchors each hair to the skin.

At its base, the follicle has the dermal papilla, which gets its nutrients to produce new hair through  the supply of blood.

The dermal papilla is the hair bulb from where the growth is the most. Each follicle produces one hair and has its own supply of blood, nerve, and muscle.

It is the dermal papilla, which has receptors to interact with the male hormones called androgens. It is the androgens, which cause the follicles to become smaller and the hair to thin. 

Is your hair dead or alive?

Small blood vessels feed the hair root at the base of the follicle. This helps the hair to grow. The hair root is alive.

The hair cells lose their nucleus as they grow upwards. Once the hair strand reaches the skin surface it consists of dead cells.

The strands that you see all over the body consist of dead cells and contain no blood vessels or nerves. It is physiologically dead. There is no feeling of any sensation when you cut your hair.

 

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