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The human hair

An important feature of mammals is that they are covered with hair. Human people, related to mammals, have various kinds of hair:

• long hair (on the head, as beard, or hair in the armpit, or pubic hair)
• bristles (hair in noses and ears, eyelashes and eyebrows)
• fine body hair.

Hair is covering the whole body, with the exception of soles of feet, palms of hands, mucous membranes, and lips.

25 % of all hair is hair on the head. A human hair on the head (we can call him Hairy) has 90'000 to 140'000 brothers and sisters.

Hairy, the human hair on the head

Hairy grows 0.25 to 0.40 millimeters per day.

This means an average growth as follows:

1 hour = 0.0125 mm

1 day = 0.3 mm

1 week = 2.1 mm

1 month = 1 cm

1 year = 12 cm

Every day, Hairy looses up to 100 brothers ans sisters.

Hairy and his hairy siblings grow daily by a total of 30 meters.

Hairy under the microscope.

Hairy, the hair is built in a tubular way and consists primarily out of a substance, called keratin. Hairy is absorbant like a sponge. The contents of the tubular hair determines his color. The surface of the tubular structure is scale-like, covered with tiny plates. Hairy does not contain nerves or blood, however is rooted in living skin, whereby a uniform structure is formed.

The hair is divided into a shaft, the portion growing above the skin, and the hair roots anchored in the skin.

The hair root of an individual hair forms a tiny long tunnel (called a follicle) which reaches into the lower layers of the skin. At the end of the tiny tunnel there is a hair papilla. The papilla is the center of growth for the hair, it is here where nutrients are taken up from the blood.

Slightly below the surface of the skin there are sebaceous glands which supply the hair with sufficient sebum, the fatty secretion of these glands. A tiny hair-raising muscle is responsible for providing sebum from the sebaceous glands. This tiny muscle can also straighten up the hair in the case of goose pimples.

The lifespan of Hairy is 3 to 7 years in the average.

Hairy and his three phases of life.

The growth phase : Hairy sits firmly in the hair papilla, and dependent upon genetic factors, grows during 2 to 7 years.

The transitory phase: In the transitory phase of approximately 2 to 4 weeks Hairy turns himself loose from the papilla and moves slowly upward in the hair follicle.

The resting phase: After a resting phase of 2 to 4 months Hairy has reached the sebaceous gland and is ready to fall out and thus to make room for his successor.

Hairy and his menu plan.

Especially healthy for Hairy and for other hair are wholemeal products, eggs, liver, kidneys, vitamin D, herrings, salmon, carrots, green vegetables, and vitamin C.

The pigments give Hairy his color. When the human being upon whom Hairy lives turns old, then Hairy receives fewer pigments and the hair turns gray or white.