DMS. K01. Histologi Jaringan Kulit
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Transcript of DMS. K01. Histologi Jaringan Kulit
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Histology of Skin
dr. Alya Amila Fitrie, M.Kesdr. Radita Nur AnggraeniDepartment of Histology
Medical Faculty University of North Sumatera2008
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INTRODUCTION
• The heaviest single organ of the body, 16% of TBW.
• Presenting 1,2 – 2,3 m2 of surface.
• Composed of :– Epidermis : an epithelial layer
of ectodermal origin– Dermis : a layer of connective
tissue of mesodermal origin.
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Comparative thickness of the skin
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EPIDERMIS
• Consist mainly of a stratified squamous keratinized epithelium → keratinocytes.
• Three << abundant cell types :1. Melanocytes : neural crest-derived cell2. Langerhans cell : derived from bone
marrow precursor3. Merkel’s cell : neural crest-derived cell
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Five layers of keratin-producing cells (keratinocytes) :
1. Stratum basale (stratum germinativum)
2. Stratum spinosum3. Stratum granulosum4. Stratum lucidum5. Stratum corneum
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Stratum basale (Stratum germinativum)
• Single layer of basophilic columnar or cuboidal cell resting on basement membrane at the dermal-epidermal junction.
• Desmosom (+), hemidesmosom (+)• Stem cells → intense mitotic activity & is
responsible, in conjunction with the initial portion of the next layer, for constant renewal of epidermal cells.
• Human epidermis is renewed about every 15-30 days.
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Stratum spinosum• Consists of cuboidal or
slighly flattened cell, a central nucleus, a cytoplasm’s processes : bundles of keratin filaments, a spine-studded appearance (tonofilaments).
• The filaments : – Maintaining cohesion among
cells– Resisting the effect of abrasion
• Stratum basale + stratum spinosum = stratum Malpighi → mitoses
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Stratum spinosum (cont.)
Stratum spinosum of the thick skin from sole of the foot. Pararosaniline-toluidine blue. Medium magnification
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Stratum granulosum
• Consists of 3-5 layers of flattened polygonal cells,
cytoplasm filled with keratohyalin granules.
• The membrane-coated lamellar granules : containing lamellar disks that are formed by lipid bilayers. This granules : fuse with cell membrane → discharge their contents → intercellular spaces of stratum granulosum → form of sheets containing lipid
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Stratum lusidum
• Translucent, thin layer of flattened eosinophilic epidermal cells.
• Organelles & nuclei (-)• Cytoplasm : densely packed
keratin filaments• Desmosom (+) between adjacent
cells
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Stratum corneum
• Consists of 15-20 layers of flattened nonnuclea-ted keratinized cells.
• Cytoplasm : a birerfringent filamentous scleroprotein, keratin.
• After keratinization, the cells consist of only fibrillar & amorphous proteins; & thickened plasma membrane → horny cells or corneocyte
Cornified envelope lipids
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Melanocytes
• A specialized cell of the epidermis found beneath or between the cells of the stratum basale & in the hair follicles.
• Derived from neural crest cells. •Hemidesmosomes(+),
desmosome (-)
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Melanogenesis
• Tyrosinase is synthesized in the RER, accumulated in GoC → vesikel : melanosom. Melanin synthesis in the melanosom II → melanosom III → melanin granules.
• Melanin granules migrates & transferred to the keratinocytes of the malpighian layer.
http://www.ambion.com/tools/pathway/loadImage.php?pos=bl&im=images/Melanocyte%20Development%20and%20Pigmentation.jpg
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Melanocyte
• Melanin granules accumulate in the supranuclear region of the cytoplasm →
protecting from
deleterious effects
of solar radiation.
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Langerhans Cells
• Star-shaped• Location : stratum
spinosum• Bone marrow-derived• Important in immunologic skin
reaction
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Merkel’s Cells
• Generally in the thick skin of palms and soles.
• Resemble the epidermalepithelial cells, with small dense granules in cytoplasm.
• Free nerve ending at the base.
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Immunologic Activity in the Skin
• Its large size• Lymphocytes >>>• Antigen-presenting cells (APC)• Close contacts with antigenic
molecules
Epidermis has an important role in some types of immune response
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DERMIS• Dermis is connective tissue that
– Support epidermis– Binds epidermis to hypodermis
• The thickness : varies• The surface : irregular→ dermal
papillae >< epidermal ridges.• Contains 2 layers :
– Papillary layer– Reticular layer
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Papillary Layer
• Composed of :– Loose connective tissue– Fibroblasts– Other connective tissue cells : mast
cells & macrophages– Extravasated leukocytes
• Anchoring fibrils (+) : special collagen fibrils
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Reticular Layer
• Composed of : – Irregular dense connective tissue
(type I collagen)– More fibers, fewer cells.
• Contains a network of fibers of elastic system → responsible for the elasticity of the skin.
Thick section of skin stained for the fibers of the elastic
fibers. Weigert’s stain
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DERMIS (cont…)
• Rich network of blood & lymph vessels.
• Arteriovenous shunt → temperature regulation.
• In addition, dermis contains : epidermal derivatives :– Hair follicle– Sweat & sebaceous glands– Nerves
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Subcutaneous Tissue
• Consists of loose connective tissue.• Contain fat cells that vary in
number & size.• Referred to superficial fascia , >>
panniculus adiposus
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Skin & Lymphatic Vessels
• The arterial vessels → 2 plexuses :– between papillary – reticular layer– between dermis – subcutaneous tissue
• The venous → 3 plexuses :– Like arterial vessels + in the middle of the
dermis.
• Lymphatic vessels : begin as closed sacs in the papillae of dermis → form two plexuses.
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Skin Sensorial Receptors
• Free nerve endings • The expanded :
– Ruffini endings
• The encapsulated : – Vater-Pacini– Meissner– Krause.
Meissner & Paccinian corpuscle
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GLANDS OF THE SKIN
• Sweat glands- Eccrine- Apocrine
• Sebaceous glands• Mammary gland
Sweat Gland
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Sweat Gland
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Sebaceous Gland
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Sebaceous Gland
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HAIRS
Hair follicle
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NAILS
Histology of Nail
• E=eponychium, H= hyponychium, N=nail plate, DP=distal phalanx
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References
• Junqueira, L.C. & Carneiro, J. Basic Histology, Text & Atlas, 11th edition, Lange Medical Books McGraw-Hill. 2005
• Gartner, L.P. & Hiatt, J.L. Colour Textbook of Histology, Third Edition. 2007
• Kierszenbaum AL. Histology & Cell Biology, An Introduction to Pathology, 2nd ed. Mosby Elsevier. 2007
• Pakurar AS, Bigbee JW. Digital Histology, an interactive CD atlas with review text, Wiley-Liss, 2004
• Berman I, Color Atlas of Basic Histology, Second Edition, Lange, 1998.
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Terima kasih….
Terima kasih…