Final answer:
Hair cells undergo a life cycle including growth, transition, and rest phases, which are the anagen, catagen, and telogen phases respectively.
Step-by-step explanation:
Falling Out Stage of a Hair Cell
The process of hair growth and shedding revolves around three phases: the anagen phase, the catagen phase, and the telogen phase.
During the anagen phase, cells rapidly divide at the hair root, pushing the hair shaft up and out, a period lasting between 2 to 7 years.
The catagen phase is a transitional stage lasting about 2 to 3 weeks, where hair follicle growth ceases. Finally, the telogen phase is a rest period for the hair follicle lasting about 2 to 4 months with no new growth.
At the end of the telogen phase, a new anagen phase begins, producing a new hair follicle which pushes the old hair out, and thus, the cycle reiterates itself.
Hair loss occurs if more hair is shed than replaced, which can result from hormonal or dietary changes, aging, or hormonal influences.
On average, individuals shed and replace about 50 hairs per day. Hair typically grows at a rate of 0.3 mm per day during the anagen phase.