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Book

Physiology, Hair

Ezra Hoover  1 , Mandy Alhajj  2 , Jose L. Flores  3
In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan.
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Book

Physiology, Hair

Ezra Hoover et al.
Free Books & Documents

Excerpt

Hair is a component of the integumentary system and extends downward into the dermal layer, where it sits in the hair follicle. Humans have approximately five million hair follicles, which offer protection from cold and UV radiation, produce sebum, and can have a significant psychological impact when growth or structure is unbalanced.

At a microscopic level, each hair's variety in length, color, diameter, and cross-sectional shape creates the characteristic profiles seen across ethnic groups and among individuals. This activity will discuss the physiology of hair, cellular components, mechanisms of growth and differentiation, and its clinical significance.

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Conflict of interest statement

Disclosure: Ezra Hoover declares no relevant financial relationships with ineligible companies.

Disclosure: Mandy Alhajj declares no relevant financial relationships with ineligible companies.

Disclosure: Jose Flores declares no relevant financial relationships with ineligible companies.

References

    1. Buffoli B, Rinaldi F, Labanca M, Sorbellini E, Trink A, Guanziroli E, Rezzani R, Rodella LF. The human hair: from anatomy to physiology. Int J Dermatol. 2014 Mar;53(3):331-41. - PubMed
    1. Martel JL, Miao JH, Badri T, Fakoya AO. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2024. Jun 22, Anatomy, Hair Follicle. - PubMed
    1. Verhave BL, Nassereddin A, Lappin SL. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2022. Oct 10, Embryology, Lanugo. - PubMed
    1. Murphrey MB, Agarwal S, Zito PM. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2023. Aug 14, Anatomy, Hair. - PubMed
    1. Breehl L, Caban O. StatPearls [Internet] StatPearls Publishing; Treasure Island (FL): 2023. Mar 27, Physiology, Puberty. - PubMed

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