Module 8: Figure hair follicle cycle
The hair follicle cycle.
The hair follicle is divided into two regions. An upper permanent non-cycling region (grey box) contains the sebaceous gland and bulge. The latter contains the epidermal stem cells (ESCs) and the melanocyte stem cells (MSCs). The lower cycling region (red box) contains the hair bulb that produces the pigmented hair fibres. The hair cycle consists of an initial phase of epithelial cell regression (catagen), a quiescent phase (telogen) followed by growth of a new hair follicle (anagen). See the text for further details of this hair follicle cycle.