Final answer:
The hair growth cycle includes three main phases: the Anagen growth phase, the Catagen transition phase, and the Telogen resting phase. Hair grows only during the Anagen phase, slows down in the Catagen phase, and rests in the Telogen phase, after which the cycle starts anew with the Anagen phase.
Step-by-step explanation:
Hair Growth Cycle Phases
The human hair growth cycle consists of three main phases: Anagen, Catagen, and Telogen. The correct order and descriptions for these phases, as described in the question, are:
- Anagen - Growth Phase: During the anagen phase, cells divide rapidly at the root of the hair which pushes the hair shaft up and out. This phase can last several years (typically 2 to 7 years), and during this time, hair grows at a rate of approximately 0.3 mm per day.
- Catagen - Transition Phase: The catagen phase is a transitional phase that signals the end of the anagen phase. Lasting about 2 to 3 weeks, in this period, the hair follicle shrinks and growth slows down significantly as it prepares to enter the telogen phase.
- Telogen - Resting Phase: The telogen phase is the resting phase where no new hair growth occurs. This phase lasts roughly 2 to 4 months, and at its conclusion, the hair is either shed or pushed out by a new hair entering the anagen phase.
Hair loss can occur when there is an imbalance, with more hair being shed than what is replaced, which can result from hormonal, dietary changes, aging, or other factors.