Did you know that you lose between 100 and 200 hairs a day? And that the bodies are called follicles? And no matter how much cosmetic importance people assign to hair, its basic purpose is to regulate body temperature. These are some facts about hair that are important in understanding abnormalities, their causes and treatment.

Hair is formed of a hard substance called keratin, which is also what our nails and teeth are made of. It grows in a follicle that is embedded in the deepest layer of the skin called the dermis.

Hair-producing cells lie at the base of the follicle in the hair matrix. It is here that epithelial cells rapidly multiply along with the dark pigment cells called melanin and form the shaft that is visible above the skin.

Among the facts about hair, here’s an interesting one: In the average person, hair grows at the rate of about 400 microns (millionth of a metre) a day. In terms of your body clock, that’s considered pretty fast!

Types of Hair

There are different types of hair on the human body. Lanugo is the name given to the kind of hair that covers the human foetus. It is shed before the baby is born. Vellus hair is the short, fine, soft hair that covers most of the skin’s surface.

Fully-mature hair is called terminal hair, which is coarse, thick and darker than that found on the rest of the body. Terminal hair grows on the scalp, chin, under the armpits, in the pubic area and on the eyebrows.

Hair varies with race in terms of kind and colour. Typically, Asians have dark hair while Caucasian people have blond, brown or red hair. Africans have dark and coarse hair.

As a thumb rule, the lighter the colour, the finer the hair and the greater the number that grows on the body.

Curly or Straight?

It is the texture of the hair that determines whether it is straight, wavy, curly or frizzy. Texture can either be fine, medium, coarse or wiry and this depends on the diameter of the shaft.

The kind of hair you have is programmed into your genes though many try and change this with a curling iron or chemicals that straighten it “permanently”. Alas, no matter what you do, your hair will always return to what your genes had intended!

Whether your hair is straight or curly depends on the shape of your hair follicle and the angle at which each strand grows out of the follicle. For instance, curly hair grows out of the follicle at a very sharp angle.

What is Alopecia?

The two most common disorders both border on the extreme and are at opposite ends of the continuum. One is extreme hair loss or alopecia and the other is excessive hair growth and is called hirsutism.

Its full medical name is alopecia areta and is sudden and excessive hair loss. It is evenly distributed between both sexes. Alopecia is an autoimmune disease that occurs when the immune system of the body begins to attack the hair follicles.

It can also be caused by certain disorders such as allergies, thyroid disease lupus and rheumatoid arthritis. Alopecia also has a strong hereditary component.

Unwanted Hair

At the other extreme is hirsutism or a problem of unwanted hair. This disease is characterised by excess hair growth on certain areas of the body, especially the upper lip and chin, underarms, pubic area.

Sometimes it can affect the entire body. Hirsutism is caused by the presence of unusually high levels of the male hormone testosterone, which in turn could be caused by one of many conditions.

Among the most common are heredity, polycystic ovarian conditions, and the use of certain drugs and menopause, which lowers the level of the female hormone oestrogen.

Studying hair disorders, their causes and treatment requires a thorough understanding of the facts about hair and thankfully, there’s plenty of scientific research about this human attribute.

Facts about Hair! is a post from: Skincare