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. Author manuscript; available in PMC: 2015 Dec 4.
Published in final edited form as: Nature. 2015 Apr 6;522(7554):94–97. doi: 10.1038/nature14306

Extended Data Fig. 1. Hair follicle regeneration cycle.

Extended Data Fig. 1

Hair follicle growth (Anagen) is characterized by downward expansion and generation of several epithelial layers. The most external layer, the outer root sheath (ORS), consists of relatively undifferentiated basal epithelial cells. Inner layers are generated by a committed progenitor pool, the matrix, which gives rise to several differentiated layers including: companion layer, inner root sheath (IRS) and hair shaft. Following growth, the majority of the newly formed layers are lost during the regression phase (Catagen), leaving a small surviving fraction of cells that reconstitute a new stem cell/progeny (Bulge/Hair Germ) compartment at the rest phase (Telogen).