Hair

Hair is an appendage to the skin, an oblong columnar keratin structure. The part of the skin that is exposed is called "hair shaft"; the part buried in the skin is called "hair root"; the ends of the hair roots are swollen like onions and called "hair balls". Hair is usually divided into two types: bristles and bristles. The bristles are thick and dark, and can be divided into two types: one is called long hair, such as hair, beard, armpit hair, pubic hair, etc .; the other is called short hair, such as eyebrows, eyelashes, ear hair, etc. The hair is soft and pale, mainly found on the face, limbs and trunk.