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SOEKLOLA MULIADY 1006733146

PERBEDAAN KERATIN PADA KULIT DENGAN KERATIN PADA RAMBUT MAUPUN

KUKU

Keratin merupakan kelompokfibrous structural protein. Keratin merupakan struktur utamapenyusun lapisan teratas kulit manusia, maupun komponen utama rambut dan kuku.

Macammacam Keratin

Di dalam kulit serta apendiksnya terdapat dua macam keratin, yaitu keratin lunak dan keratin

keras. Keratin lunak selain terdapat pada folikel rambut juga terdapat di permukaan kulit. Keratin

lunak dapat diikuti terjadinya pada epidermis yang dimulai dari stratum granulosum dengan butir-butir keratohyalinnya, kemudian sel-sel menjadi jernih pada stratum lucidum dan

selanjutnya menjadi stratum korneum yang dapat dilepaskan. Sedangkan keratin keras terdapat

pada cuticula, cortex rambut dan kuku. Keratin keras dapat diikuti terjadinya mulai dari sel-sel

epidermis yang mengalami perubahan sedikit demi sedikit dan akhirnya berubah menjadi keratinkeras yang lebih homogen. Keratin keras juga lebih padat dan tidak dilepaskan, serta tidak begitu

reaktif dan mengandung lebih banyak sulfur.1,2

Gambar 1. Gambar Mikroskopis struktur filament keratin di dalam sel.2

DAFTAR PUSTAKA

1. Anonymous. Histologi Kulit. Diakses dari: http://blogs.unpad.ac.id/histologi/2010/

07/18/10-kulit/ pada tanggal 12 februari 2011.2. Hickman, Cleveland Pendleton; Roberts, Larry S.; Larson, Allan L. (2003). Integrated

principles of zoology. Dubuque, IA: McGraw-Hill. p. 538. ISBN0-07-243940-8.

http://blogs.unpad.ac.id/histologi/2010/%2007/18/10-kulit/http://blogs.unpad.ac.id/histologi/2010/%2007/18/10-kulit/http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/0-07-243940-8http://en.wikipedia.org/wiki/Special:BookSources/0-07-243940-8http://en.wikipedia.org/wiki/File:KeratinF9.pnghttp://blogs.unpad.ac.id/histologi/2010/%2007/18/10-kulit/http://blogs.unpad.ac.id/histologi/2010/%2007/18/10-kulit/http://en.wikipedia.org/wiki/International_Standard_Book_Numberhttp://en.wikipedia.org/wiki/Special:BookSources/0-07-243940-8

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Diambil dari: http://www.telemedicine.org/anatomy/anatomy.htm judul:

ANATOMY OF THE SKIN,

Maged N. Kamel, M.D.

Keratin

Electron microscopical examination of cells from all tissues reveals that they contain a

complex, heterogenous, intracytoplasmic system of filaments. The components of this

system include actin, myosin, and tubulin, whose diameters average approximately 60A,150A, and 250A, respectively. In addition, other intracytoplasmic filaments were noted,

and since the diameter of these latter structures was found to be between 70 and 100A,

they were called intermediate filaments.

Intermediate filaments form a major part of the cytoskeleton of most cells and fulfill a

variety of roles related to cell shape, spatial organization, and perhaps informationaltransfer. The nucleus contains structures related to these intermediate filaments and many

intracellular components including polyribosomes, mitochondria, nucleic acids, enzymes,

and cyclic nucleotides are attached to the cytoskeleton.

Based on their biochemical, biophysical, and antigenic properties, a number of classes of

intermediate filaments can be recognized in different cell types: desmin (skeletin) inmuscle cells, glial fibrillary acidic filaments in glial cells, neurofilaments in neurons,

vimentin in mesenchymal cells, and keratin in epithelial cells. In cultured epidermal cells,

keratins account for up to 30% of the cellular protein, while in stratum corneum, keratinaccounts for up to 85% of the cellular protein.

At least 19 keratin proteins can be identified ranging in molecular weight fromapproximately 40,000 to 68,000 micrograms. Moll and his coworkers published their

human keratin catalogue in 1982. According to this catalogue, there are two keratin

subfamilies. The molecular weight of the members of one (the basic subfamily) is

relatively larger than that of the members of the other (the acidic subfamily). Each of thekeratins is the product of a unique gene and, in essentially all situations, the keratins are

expressed as pairs containing one member of each subfamily. The two members of each

pair are in the same size rank order within their respective family, e.g., the largest acidic

keratin is expressed with the largest basic.

The type of keratin differs in different tissues, i.e, there are different types of keratin forkeratinized epidermis, hyperproliferative epidermis of palms and soles, corneal

epithelium, stratified epithelium of the esophagus and cervix, and simple epithelium of

the epidermal glands. As mentioned before, keratin is the main structural protein of the

epidermis.

http://www.telemedicine.org/anatomy/anatomy.htmhttp://telemedicine.org/anatomy/anatomy.htm#tophttp://telemedicine.org/anatomy/anatomy.htm#tophttp://telemedicine.org/anatomy/anatomy.htm#tophttp://telemedicine.org/anatomy/anatomy.htm#tophttp://telemedicine.org/anatomy/anatomy.htm#tophttp://www.telemedicine.org/anatomy/anatomy.htm

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The keratinocytes in the basal layer and prickle cell layer synthesize keratin filaments

(tonofilaments) which aggregate into bundles (tonofibrils). Eventually, in the cells of the

stratum corneum, these bundles of keratin filaments form a complex intracellular networkembedded in an amorphous protein matrix. The matrix is derived from the keratohyaline

granules of the granular layer. Epidermal keratinization results in the production of a

barrier which is relatively impermeable to substances passing in or out of the body.

http://telemedicine.org/anatomy/anatomy.htm#top