Hair Follicle Bulge and Stem Cell Cycles

The hair follicle bulge is the stem cell niche that helps control hair growth and renewal. A hair follicle is a small part of the skin that produces the hair shaft. Paul Gerson Unna was the first to observe the bulge in the outer root sheath, or ORS.

The bulge sits between the sebaceous gland and...

Hair grows through a tube-like structure under the skin called a hair follicle. The bulge is a small part of the hair follicle that is the niche for hair follicle stem cells or HFSCs.

HFSCs can differentiate into most skin epithelial cells, including keratinocytes and hair follicle cells. These stem cells allow the hair follicle...