Hair

The filamentous outgrowth from the scalp. The hair [of the head] is the external bloom of the kidney and is the surplus of the blood. Plain Questions (素问 sù wèn, shàng gǔ tiān zhēn lùn) states ... When kidney qì is replete, the hair grows and the teeth change... ... When kidney qì is debilitated, the hair falls and the teeth desiccate. Diseases of the hair include dry hair; graying of the hair; hair loss.