human hair chapter1
human hair normally means hair grow on head,hair is not organ,so not including nerve,blood vessel and cells,besides let people looks more beauty,the most important thing for hair is protect the head.soft and fluffy hair have elastic,can resist slightly collision,also can help sweat evaporation from head.normally a people have around 1/10million hair for a whole head.
hair color decided by gene。the most hair color we see are black,golden,brown and red.and when people get old,hair normally will become white.in the world as different district and nation,There are black, yellow, red brown, red brown, yellow, gray, and even green and red.through dye hair,can let hair become variety kinds of colors.Scientific research has proven that the metal elements contained in the color of the hair with the hair in the different relevant. Hair contains the same amount of copper, iron andmelanin, when increasing the nickel content, becomes gray. Golden yellow hair contains titanium, molybdenum containing red brown hair, red brown in addition to containing copper, iron, and cobalt, green hair is contained too much copper. In some countriesAfrica, some children's hair was red, is the result of a serious lack of protein.
the water absorption of the hair
and normally hair contains around 10% water.
Porous hair refers to hair can absorb water amount, hair color, perm and hair are porousabout.
There is a close relationship between the properties of heat and hair hair, usually heated to 100 degrees, the hair began to have extreme variation, finally dissolved carbide
the physiology of hair
The lag phase of hair, normal daily off 70---100 the root hair, also have the same amount of hair regeneration. Different parts of the hair growth cycle length and different length ofabout. The growth cycle of eyebrows and eyelashes for only 2 months, so short. Hair growth is affected by genetic, health, nutrition and hormone level and so on the many kinds of factors.