Hair is an embellishment of any person, and, to keep its beauty one should carefully look after his or her hair. To succeed we should know what hair is.
3 % of our hair is water and 97% - protein. Proteic substance keratin is rich in sulfur, microelements and vitamins.
The part of hair independently located under the skin is called core and the part hidden deep in skin hair root. The root ends with widening - hair bulb where hair grows.
Hair core consists of three layers. Hair marrow is called medullary substance and contains keratinized cells. Major hair constituent is cortical substance composed of oblong tight cells containing pigment - staining agent. This stain can be red, yellow and black and combinations of these colors create individual hair coloration. Upon stain absence hair is blond. Hair periblast consists of squamous keratinized cells arranged in one row and stratified like tiling.
Hair root is located in hair follicle. Every hair has unstriped ribbon-shaped muscles connected in one end by short tendon with compact layer of derma, and in another end with a place below the oil gland orifice. Contracting muscle lifts a hair compressing oil gland thus contributing to secretion.
Hair growth is cyclic. The cycle takes years followed by several months of rest. Thereupon old hair falls out and new cycle takes place. The fastest growing is head hair; the slowest eyebrow hair. One separate hair lives on average from several months to six years. Its normal if over the day you lose 30 to 50 hairs.
Hair covers the whole human body excluding palms and soles. An adult person has approximately 100 000 hairs, yet the quantity depends on color. Blonds have the biggest number of hairs up to 150 000. Black-skinned have the thickest hair that can be three times thicker than blond.
Healthy hair is usually strong and resilient. A hair can be stretched by 1/5 of its length and after that it returns to its initial state. By strength hair can be compared to aluminium and able to take a load of 100 to 200g. Hair is hygroscopic, i.e., it can take up. Its highly stable to weak acids, yet doesnt endure alkaline mixtures.
For people hair plays considerable role. Firstly, its a perfect adornment emphasizing charm, concealing defects, and, secondly it has many vital functions: hair prevents our heads from overheating and overcooling.