A hair normally grows from each follicle for about three years, is then shed, and a new hair grows.

一根头发通常从每个毛囊中生长约三年，然后脱落，然后一根新头又生长。

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Hair is dead, and once the main shaft of the hair follicle is extruded, expired biomass can't be tinted or bleached by psychological trauma or fear.

头发是死的，一旦其毛囊主轴受到挤压，其生物物质由于心理创伤或恐惧不能着色或漂白。

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The arrectores pilorum are attached to the hair follicles below the sebaceous glands and, in contracting, pull the hair follicle upward, producing gooseflesh.

立毛肌附着于皮脂腺之下的毛囊，当它收缩时，牵拉毛囊直立，产生鸡皮疙瘩。

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Common problems include overactive oil glands, bacteria growth within follicles and pores and problems with the keratinization process, where cells are normally sloughed off the skin, pushed out of the hair follicle and replaced by new cells.

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Although it is understandably tight-lipped about the exact mechanism behind its success, one probably enlists the help of cells called keratinocytes, which interact naturally with the dermal papilla cells of the hair follicle and secrete a chemical factor that supports their growth.

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