Cuticle (hair)

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Comparison of sheep (top) and human (bottom) hairs with different cuticle textures CSIRO ScienceImage 8115 Human hair and Merino wool fibre.jpg
Comparison of sheep (top) and human (bottom) hairs with different cuticle textures

The hair cuticle is the outermost part of the hair shaft. [1] It is formed from dead cells, overlapping in layers, which form scales that strengthen and protect the hair shaft. [2] [3] . These layers are formed of keratin proteins [4] . The hair cuticle is also known to contain anteiso-18-methyleicosanoic acid which contribute to the hydrophobic properties of hair. [5] [4]

Diagram of the hair shaft, indicating medulla (innermost), cortex, and cuticle (exterior) Hair shaft diagram.png
Diagram of the hair shaft, indicating medulla (innermost), cortex, and cuticle (exterior)

While the cuticle is the outermost layer, it is not responsible for the color of the hair. Melanin is the pigment that gives hair its color and is found in the cortex. [6]

See also

Related Research Articles

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<span class="mw-page-title-main">Skin</span> Soft outer covering organ of vertebrates

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Keratin is one of a family of structural fibrous proteins also known as scleroproteins. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, and the outer layer of skin among vertebrates. Keratin also protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. Excessive keratinization participate in fortification of certain tissues such as in horns of cattle and rhinos, and armadillos' osteoderm. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin comes in two types, the primitive, softer forms found in all vertebrates and harder, derived forms found only among sauropsids.

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<span class="mw-page-title-main">Stratum corneum</span> Outermost layer of the epidermis

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Artificial hair integrations, more commonly known as hair extensions, hair weaves, and fake hair add length and fullness to human hair. Hair extensions are usually clipped, glued, or sewn on natural hair by incorporating additional human or synthetic hair. These methods include tape-in extensions, clip-in or clip-on extensions, micro/nano rings, fusion method, weaving method, and wigs.

<span class="mw-page-title-main">Hair care</span> Hygiene and cosmetology involving human hair

Hair care or haircare is an overall term for hygiene and cosmetology involving the hair which grows from the human scalp, and to a lesser extent facial, pubic and other body hair. Hair care routines differ according to an individual's culture and the physical characteristics of one's hair. Hair may be colored, trimmed, shaved, plucked or otherwise removed with treatments such as waxing, sugaring and threading. Hair care services are offered in salons, barbershops and day spas, and products are available commercially for home use. Laser hair removal and electrolysis are also available, though these are provided by licensed professionals in medical offices or speciality spas.

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The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruit body. It covers the trama, the fleshy tissue of the fruit body. The pileipellis is more or less synonymous with the cuticle, but the cuticle generally describes this layer as a macroscopic feature, while pileipellis refers to this structure as a microscopic layer. Pileipellis type is an important character in the identification of fungi. Pileipellis types include the cutis, trichoderm, epithelium, and hymeniderm types.

<span class="mw-page-title-main">Plant cuticle</span> Waterproof covering of aerial plant organs

A plant cuticle is a protecting film covering the outermost skin layer (epidermis) of leaves, young shoots and other aerial plant organs that have no periderm. The film consists of lipid and hydrocarbon polymers infused with wax, and is synthesized exclusively by the epidermal cells.

The inner root sheath or internal root sheath of the hair follicle is located between the outer root sheath and the hair shaft. It is made of three layers: Henle's layer, Huxley's layer, and the cuticle. The inner root sheaf serves to protect growing hair.

A cuticle, or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non-homologous, differing in their origin, structure, function, and chemical composition.

<span class="mw-page-title-main">Cortex (hair)</span>

The cortex of the hair shaft is located between the hair cuticle and medulla and is the thickest hair layer. It contains most of the hair's pigment, giving the hair its color. The major pigment in the cortex is melanin, which is also found in skin. The distribution of this pigment varies from animal to animal and person to person. In humans, the melanin is primarily denser nearer the cuticle whereas in animals, melanin is primarily denser nearer the medulla.

<i>Piedraia hortae</i> Species of fungus

Piedraia hortae is a superficial fungus that exists in the soils of tropical and subtropical environments and affects both sexes of all ages. The fungus grows very slowly, forming dark hyphae, which contain chlamydoconidia cells and black colonies when grown on agar. Piedraia hortae is a dermatophyte and causes a superficial fungal infection known as black piedra, which causes the formation of black nodules on the hair shaft and leads to progressive weakening of the hair. The infection usually infects hairs on the scalp and beard, but other varieties tend to grow on pubic hairs. The infection is usually treated with cutting or shaving of the hair and followed by the application of anti-fungal and topical agents. The fungus is used for cosmetic purposes to darken hair in some societies as a symbol of attractiveness.

<span class="mw-page-title-main">Loose anagen syndrome</span> Medical condition

Loose anagen syndrome, also known as loose anagen hair syndrome, is a hair disorder related to dermatology. It is characterised by the easy and pain free detachment of anagen staged hairs from the scalp. This hair condition can be spontaneous or genetically inherited.

Alpha-keratin, or α-keratin, is a type of keratin found in mammalian vertebrates. This protein is the primary component in hairs, horns, claws, nails and the epidermis layer of the skin. α-keratin is a fibrous structural protein, meaning it is made up of amino acids that form a repeating secondary structure. The secondary structure of α-keratin is very similar to that of a traditional protein α-helix and forms a coiled coil. Due to its tightly wound structure, it can function as one of the strongest biological materials and has various functions in mammals, from predatory claws to hair for warmth. α-keratin is synthesized through protein biosynthesis, utilizing transcription and translation, but as the cell matures and is full of α-keratin, it dies, creating a strong non-vascular unit of keratinized tissue.

References

  1. James, William; Berger, Timothy; Elston, Dirk (2005) Andrews' Diseases of the Skin: Clinical Dermatology (10th ed.). Saunders. Page 8. ISBN   0-7216-2921-0.
  2. "Hair!". Worsleyschool.net. Retrieved 2016-06-13.
  3. "Hair". British Medical Association Complete Family Health Encyclopedia. Dorling Kindersley Limited. 1990.
  4. 1 2 "Known and Unknown Features of Hair Cuticle Structure: A Brief Review". Cosmetics.
  5. "The role of 18-methyleicosanoic acid in the structure and formation of mammalian hair fibres". Micron.
  6. "Hair biology - hair fiber". Keratin.com. Archived from the original on 2020-08-01. Retrieved 2013-08-18.