bombscience
Senior Member
- Reaction score
- 7
Today Class, we are going to review the phases of hair growth:
A hair follicle is a stocking-like structure that contains several layers with different jobs. At the base of the follicle a projection is formed like sticking a finger in the bottom of a stocking and pushing it in a small amount. This projection is called the papilla and it contains capillaries, or tiny blood vessels, that feed the cells.
The living part of the hair is bottom part of the stocking surrounding the papilla called the bulb. This bottom part is the only part fed by the capillaries. The cells in the bulb divide every 23 to 72 hours, faster than any other cells in the body.
The papilla is the very bottom portion of the hair follicle that contains the blood supply and the matrix. The matrix consists of cells that actually form the hair shaft. The papilla is active during the anagen phase, is separated from the hair shaft during the catagen phase, and is completely inactive during the telogen phase.
Anagen is the active growth phase of hair follicles. The cells in the root of the hair are dividing rapidly, adding to the hair shaft. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active phase of growth for 2-6 years. The amount of time the hair follicle stays in the anagen phase is genetically determined. At the end of the anagen phase an unknown signal causes the follicle to go into the catagen phase.
The catagen phase is a short transition stage that occurs at the end of the anagen phase. It signals the end of the active growth of a hair. This phase lasts for about 2-3 weeks while a club hair is formed.
A club hair is formed during the catagen phase when the part of the hair follicle in contact with the lower portion of the hair becomes attached to the hair shaft. This process cuts the hair off from its blood supply and from the cells that produce new hair. When a club hair is completely formed, about a 2 week process, the hair follicle enters the telogen phase.
The telogen phase is the resting phase of the hair follicle. At any given time, 10%-15% of all hairs are in the telogen phase. This phase lasts for about 100 days for hairs on the scalp and much longer for hairs on the eyebrow, eyelash, arm and leg. During this phase the hair follicle is completely at rest and the club hair is completely formed. Pulling out a hair in this phase will reveal a solid, hard, dry, white material at the root. About 25-100 telogen hairs are shed normally each day.
A hair follicle is a stocking-like structure that contains several layers with different jobs. At the base of the follicle a projection is formed like sticking a finger in the bottom of a stocking and pushing it in a small amount. This projection is called the papilla and it contains capillaries, or tiny blood vessels, that feed the cells.
The living part of the hair is bottom part of the stocking surrounding the papilla called the bulb. This bottom part is the only part fed by the capillaries. The cells in the bulb divide every 23 to 72 hours, faster than any other cells in the body.
The papilla is the very bottom portion of the hair follicle that contains the blood supply and the matrix. The matrix consists of cells that actually form the hair shaft. The papilla is active during the anagen phase, is separated from the hair shaft during the catagen phase, and is completely inactive during the telogen phase.
Anagen is the active growth phase of hair follicles. The cells in the root of the hair are dividing rapidly, adding to the hair shaft. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active phase of growth for 2-6 years. The amount of time the hair follicle stays in the anagen phase is genetically determined. At the end of the anagen phase an unknown signal causes the follicle to go into the catagen phase.
The catagen phase is a short transition stage that occurs at the end of the anagen phase. It signals the end of the active growth of a hair. This phase lasts for about 2-3 weeks while a club hair is formed.
A club hair is formed during the catagen phase when the part of the hair follicle in contact with the lower portion of the hair becomes attached to the hair shaft. This process cuts the hair off from its blood supply and from the cells that produce new hair. When a club hair is completely formed, about a 2 week process, the hair follicle enters the telogen phase.
The telogen phase is the resting phase of the hair follicle. At any given time, 10%-15% of all hairs are in the telogen phase. This phase lasts for about 100 days for hairs on the scalp and much longer for hairs on the eyebrow, eyelash, arm and leg. During this phase the hair follicle is completely at rest and the club hair is completely formed. Pulling out a hair in this phase will reveal a solid, hard, dry, white material at the root. About 25-100 telogen hairs are shed normally each day.
