Petit Science. The structure of a 0.1mm diameter beard (body hair)


Cross-section of the hair shaft.

There are two types of hairs in a beard: hard hairs and pubic hairs.
Among the hard hairs there are very fine, pigment-poor pubic hairs of about 0.01mm in diameter. Hard hairs are about 0.1 mm in diameter and are surrounded by a hard scaly outer layer (cuticle) around a pigmented, flexible furry substance. At the center of the fur coat, there is a central axis called the medulla. Bald hairs are almost identical to hard hairs, except that there is no medulla. There are between 6,000 and 25,000 round or oval-shaped hard hairs on the face of an adult male. The speed at which a beard grows varies considerably from person to person and from place to place, but it grows at an average rate of about 0.4 mm in a 24-hour period.

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The beard stretched for 24 hours.

Also, the distribution of beards is not uniform. The least hair is on the underside of the cheeks (18 to 36 cm2), and the densest growth is on the upper lip area (75 to 110 cm2). In general, hairs grow at an angle of 30 to 60 degrees from the surface of the skin. Most hairs are related to sebaceous glands, and the hairs are covered with oils secreted from them.
An important property of hair is that it becomes flexible when it gets wet. The strength of wet hairs drops to 1/2 to 1/3 of the strength of dry hairs, which affects the comfortable shave that makes the razor blade last longer
It is a giving factor. Later on, the skin treatment before shaving is an important element of shaving, and if you do it properly, you can get a comfortable shave by removing the grease that covers the surface of the hair, allowing water to penetrate and soften the hair, etc.

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The Skin

Cross-section of the skin

The skin is never smooth, and the elasticity varies from place to place. The skin is made up of two layers, the thin epidermis and the thick dermis below it, and the hair roots are in the dermis. The epidermis is further divided into several layers. The stratum corneum is made up of dead cells that are constantly peeling off, and wet shaving using water clearly and efficiently removes these dead cells. An analysis of the shaving shavings reveals skin debris fragments in roughly the same amount as the hairs.
New cells proliferate from below the epidermis and reach the surface of the skin in about 10 to 20 days. After that, the skin we see can be said to be less than 20 days old.

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