The anagen phase of the hair follicle cycle is when the follicle is configured to grow hair. In short hairs (e.g., mouse underhairs and human eye lashes) anagen phase is short, but in the wool of sheep and in human scalp hair anagen is a prolonged state lasting for years. In this chapter we describe the morphological and biological divisions within the anagen follicle.
Keywords: Developmental zones; Hair development; Hair follicle; Inner root sheath; Morphology.