Inside the hair
The hair follicle consists of the hair bulb, the inner root sheath and the hair shaft. The hair bulb is onion-shaped and has a cavity in which the dermal papilla is embedded. The bulb contains the hair matrix, the germ layer which forms the inner root sheath, and the hair shaft made up of medulla, cortex and cuticle. It obtains its nutrients via blood vessels. The outer root sheath completely surrounds the hair follicle and, together with the inner sheath, secures the hair shaft within the follicle. The sebaceous gland is situated in the upper follicle, as is the erector muscle of the hair.
