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  1. May 03, 2017 · Hair is a derivative of the epidermis and consists of two distinct parts: the follicle and the hair shaft. The follicle is the essential unit for the generation of hair. The hair shaft consists of a cortex and cuticle cells, and a medulla for some types of hairs. Hair follicle has a continuous growth and rest sequence named hair cycle.

    • Bilgen Erdoğan
    • 4
    • 2017
  2. Apr 29, 2021 · The hair structure divides into the hair shaft and hair follicle. The hair shaft is the portion of the hair that is visible on the outside of the skin. It is made up of cuticle cells that surround the cortex, with a central medulla present in thicker hair. The cortical layer provides the bulk of the hair shaft structure and is comprised of keratin.

    • Hani Yousef, Julia H. Miao, Mandy Alhajj, Talel Badri
    • 2
    • 2020
  3. Jul 29, 2019 · Hair Anatomy – A simple overview. Hair is an appendage of a layer of skin called the epidermis (the outer layer). It consists of two distinct parts namely the hair follicle and the hair shaft. The Hair follicle is the basic unit for the generation of hair.

    • Abstract
    • Introduction
    • Plucked Hair Shaft Anatomy and Integrity
    • Stem Cells and Plucked Hair Shafts
    • Gene Expression Profiling
    • Diagnostic and Clinical Applications of Plucked Hair
    • Perspectives
    • Acknowledgment

    The hair follicle is a skin integument at the boundary between an organism and its immediate environment. The biological role of the human hair follicle has lost some of its ancestral importance. However, an indepth investigation of this miniorgan reveals hidden complexity with huge research potential. An essential consideration when dealing with human research is the awareness of potential harm and thus the absolute need not to harm—a rule aptly qualified by the Latin term “primum non nocere” (first do no harm). The plucked hair shaft offers such advantages. The use of stem cells found in hair follicles cells is gaining momentum in the field of regenerative medicine. Furthermore, current diagnostic and clinical applications of plucked hair follicles include their use as autologous and/or three-dimensional epidermal equivalents, together with their utilization as surrogate tissue in pharmacokinetic and pharmacodynamics studies. Consequently, the use of noninvasive diagnostic procedu...

    The hair follicle is a skin integument at the boundary between an organism and its immediate environment. It is the evolutionary relative of the scale, feather, and nail, integuments that have served an essential role in the survival of organisms [1 1. P. Wu, L. Hou, M. Plikus et al., “Evo-Devo of amniote integuments and appendages,” International Journal of Developmental Biology, vol. 48, no. 2-3, pp. 249–270, 2004. View at: Publisher Site| Google Scholar See in References ]. The biological role of the human hair follicle has lost some of its ancestral importance; however, an indepth investigation of this miniorgan reveals hidden complexity with huge research potential. The authors Paus and Foitzik describe the hair follicle as having a unique mammalian characteristic with a stem cell-rich, prototypic neuroectodermal-mesodermal interaction system. It is described as a mammalian organ undergoing cyclic transformations from stages of rapid growth (anagen) to apoptosis-driven regressi...

    The intact hair follicle (see Figure 1) can be simply described from a histological point of view as a minute cluster of uniform epithelial cells, adjacent to a similar sized aggregation of uniform mesenchymal cells. It is an organ composed of five or six concentric cylinders, each of which is composed of cells of a distinctive type, synthesizing their own distinctive set of proteins [3 1. M. H. Hardy, “The secret life of the hair follicle,” Trends in Genetics, vol. 8, no. 2, pp. 55–61, 1992. View at: Google Scholar See in References ]. A detailed biology of the intact hair follicle can be found in the article published by Paus and Cotsarelis [4 1. R. Paus and G. Cotsarelis, “The biology of hair follicles,” The New England Journal of Medicine, vol. 341, no. 7, pp. 491–497, 1999. View at: Publisher Site| Google Scholar See in References ]. Obtaining an intact hair follicle is only possible by means of a skin biopsy. This invasive procedure restricts the availability, mainly to tissue...

    The epidermis harbours two stem cell repositories, one found in the basal layer of interfollicular epidermis and the other in the hair follicle. The use of stem cells found in hair follicles cells is gaining momentum in the field of regenerative medicine. This has created the need to identify the exact site in the hair follicle and to design simple methods to access such cells such as from plucked hair follicles that are readily available. Moll performed studies on the localization of colony-forming cells in human plucked hair shafts [11 1. I. Moll, “Proliferative potential of different keratinocytes of plucked human hair follicles,” Journal of Investigative Dermatology, vol. 105, no. 1, pp. 14–21, 1995. View at: Google Scholar See in References ]. The investigators utilised anagen scalp plucked hairs to confirm the presence of an intact outer root sheet as well as the proliferative potential of the different keratinocytes [11 1. I. Moll, “Proliferative potential of different kerati...

    Gene expression profiling (GEP) is an important research avenue for understanding how cells and tissues function under normal conditions, characterizing the responses to toxicological or pharmaceutical exposures and elucidating molecular mechanisms associated with aging, disease development, and progression. Several authors have used RT-qPCR to analyze the expression of a limited number of genes in adult plucked human hair follicles [29 1. Y. F. Mahé, B. Buan, N. Billoni et al., “Pro-inflammatory cytokine cascade in human plucked hair,” Skin Pharmacology, vol. 9, no. 6, pp. 366–375, 1996. View at: Google Scholar See in References –31 1. K. Stark, H. Törmä, M. Cristea, and E. H. Oliw, “Expression of CYP4F8 (prostaglandin H 19-hydroxylase) in human epithelia and prominent induction in epidermis of psoriatic lesions,” Archives of Biochemistry and Biophysics, vol. 409, no. 1, pp. 188–196, 2003. View at: Publisher Site| Google Scholar See in References ]. Kim et al. highlight the fact th...

    Plucked hair shafts are becoming a useful diagnostic tool in dermatological conditions. Direct immunofluorescence (DIF) of perilesional skin is the gold standard in the diagnosis of pemphigus [35 1. R. Rao, K. Dasari, S. Shenoi, and C. Balachandran, “Demonstration of pemphigus-specific immunofluorescence pattern by direct immunofluorescence of plucked hair,” International Journal of Dermatology, vol. 48, no. 11, pp. 1187–1189, 2009. View at: Publisher Site| Google Scholar See in References ]. Rao et al. have used the ORS of plucked anagen hair shafts to detect pemphigus specific immunofluorescence pattern and concluded that DIF of plucked hair is a simple, noninvasive test that in future may alleviate the need for skin biopsies in patients with pemphigus [35 1. R. Rao, K. Dasari, S. Shenoi, and C. Balachandran, “Demonstration of pemphigus-specific immunofluorescence pattern by direct immunofluorescence of plucked hair,” International Journal of Dermatology, vol. 48, no. 11, pp. 1187...

    The plucked hair shaft has been used in medical research over the last 60 years. This “mini” organ is becoming an important testing ground in biomedical research. A most exciting role for plucked hair shafts is developing in the field of stem cell reprogramming and the development of autologous epidermal equivalents. The use of plucked hair shaft as surrogate tissue in phase 1 trials for chemotherapeutic drug development as well as its use as a surrogate tissue model in systems biology approaches to medical research will become more important in the immediate future.

    The authors would like to thank Mr. Anton Abela (Department of Clinical Pharmacology and Therapeutics, Faculty of Medicine and Surgery, University of Malta) for designing the figure presented in this paper.

    • Kevin Schembri, Christian Scerri, Duncan Ayers, Duncan Ayers
    • 5
    • 2013
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  5. 210000004919 Hair shaft Anatomy 0.000 description 12 238000007598 dipping method Methods 0.000 description 12 239000000126 substance Substances 0.000 description 12

    • Diann Bennett Ernestine, Von Soden Adolph F Graf
    • 14
    • 1962
  6. The inner root sheath (IRS) is an important structure of the lower part of the hair follicle that surrounds and protects the growing hair. It lies between the hair in the center and the outer root sheath (ORS) peripherally, and all these three structures are derived from the matrical cells of the follicular bulb.

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