keratinized       
adjective  biology, medical specialized (UK usually keratinised) uk/ˈker.ə.tɪn.aɪzd/ us/ˈker.ə.tən.aɪzd/
 角质化的
having changed into, or changed so as to contain, keratin (= the main substance that forms hair, nails, horns, feathers, etc.) 
  A hair is a thread-like structure consisting of dead keratinized cells. 毛发是由死亡的角质化细胞组成的束状结构。 
 The surface of the lesion was highly keratinized. 病灶表面高度角质化。 
 - More examples
 - The deeper cell layers of the epidermis proliferate, with the cells gradually passing towards the surface and becoming keratinized as they do so.
 - The treatment is useful for heavily keratinized warts.
 - The fungus has been found inside the keratinized cells of the epidermis of adult or newly metamorphosed animals.
 - The seal's eye is protected on land and underwater by the strongly keratinized corneal epithelium.