How+does+hair+grow?


 * __HOW DOES HAIR GROW?__**

Answer the question below, append new answers to the top of this page. _ __Response 1:__ How does hair grow? Hair grows in three phases. The anagen or growing phase, the catagen or transitional phase, and the telogen or resting phase. The anagen phase last from 2-8 years. In this phase growth cells in the papilla quickly divide and produce the hair shaft which becomes keratinized as it pushes up and out of the follicle into the pore, much like a plant growing. The roots of a plant take nutrients from the earth, much like a hair follicle take nutrients from the skin. The follicle grows down deeper into the skin to get nourishment. The next phase is the catagen phase. This is where the follicle shrinks, and the hair stops growing, but does not fall out. Durring this phase the follicle shrinks in length to about 1/6 of its original size. The hair shaft is pushed up as the follicle disintegrates. The last phase is called the telogen phase. This is where the hair does not grow, but is still attached to the follicle. After this phase in the cycle is done, the hair goes back into the anagen phase. It is at this time when the new hair shaft is forming, that the old hair is pushed out and lost. The number of active follicles goes down by 30-50% between the ages of 30 and 50.
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Word Definitions: Catagen: Transitional phase of the hair cycle. Transitional: A period of transition or change, movement or passage from one state to the other. Anagen: Growing phase of a hair follicle. Follicle: Small cavity sac or gland. Papilla: A small vascular process at the root of a hair. Vascular: Pertaining to, composed of, or provided with vessels or ducts that carry fluids, such as blood. Telogen: A phase of the hair cycle following the anagen phase.

Sadie Clark, December 6th 2011 http://www.hairlosshelp.com/hair_loss_research/hair.cfm http://www.encyclopedia.com/topic/hair.aspx - From Encyclopedia of Aging, 2002, Ross, J. Barrie http://dictionary.reference.com/

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