头发的结构（Hair structure）.docVIP

头发的结构（Hair structure） What is hair? A group of keratinized cell proteins Keratin: a protein with a strong structure Horny protein: soft horny - the horny layer of the epidermis of the skin Horniness - hair, nails Since it is keratin protein, so the hair of the hair does not have the ability to deliver nutrients, so the health of the hair on the need to rely on external supplement, both by the hair care steps to achieve the purpose of healthy hair Hair growth Generally speaking: 1-2cm/ months, more than 3cm slow down, spring and summer faster than winter, women faster than men, night faster than the day, 16-24, the fastest growing, more than 65 years old gradually slow Hair cycle: average life expectancy is 2-6 years, average hair loss 50-100 / day The relationship between hair and pH Average pH value of hair: 4.5-5.6; average pH value of skin surface 5.5-5.6; weak acid Hair containing saturated water can expand 31.2% When PH=4-6, hair stays pristine, and this is the most difficult environment for bacteria and viruses to survive When PH is more than 9.5, it expands rapidly, softens and corrode When PH is 4.5-5.6, the hair forms an isoelectric point. At this point, the hair fiber is the strongest and strongest, and the hair is the healthiest When the PH is greater than 9.6, the key structure in the hair melts and the hair expands too much (like a balloon that breaks) When PH is less than 2, the hair will expand slightly, and the damage will be great (loss of quality, become empty) A component of hair A healthy hair can withstand 100 grams of weight, too much comb brush will cause damage to the epidermis, when the hair is moist, the epidermis scales open, expansion, and vulnerable to injury, at this time the hair is 5 - 10 times sensitive A hair consists of the epidermis, the cortex, and the medulla Outer epidermis (CUTICLE) (10%-13%) Concept: the hair coat is the outermost layer of hair, which is keratinized, flat, nuclear free cell, such as scaly, overlapping (about