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BIO 211 - 05 - Integumentary System.pptx - 5 The...

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55The IntegumentarySystemLecture Presentation byChasity O’Malley, Palm Beach State Collegewith Notes byLori Garrett, Parkland College
Levels of Organization
Integumentary SystemSkin orintegument(covering)Body’s first line of defense against environmentTwo major components1.Cutaneousmembrane2.Accessorystructures
Integumentary System1.Cutaneous membraneEpidermis(epi, above)Stratified squamousepitheliumDermisPapillary layer (areolarconnective tissue)Reticular layer (denseirregular connective tissue)
Integumentary System2.Accessory structuresHairsNailsExocrine glandsSebaceous (oil) glandsSweat glandsSensory receptors andnerve fibersArrector pili musclesCutaneous plexus(networkof blood vessels)
Integumentary SystemSubcutaneous layer(hypodermis, below-dermis)NOTpart of integumentSeparates integument fromdeep fascia
Epidermis
EpidermisMultiple layers of cells (strata)Primary cell type in epidermis iskeratinocyteDeeper layers of epidermis formepidermalridgesAdjacent todermalpapillaeIncrease surface area for better attachment
Epidermis1.StratumbasaleAttached to basementmembrane byhemidesmosomesMost cells here arebasalcells, stem cells thatdivide to replace moresuperficial keratinocytes
Epidermis2.Stratum spinosum(“spinylayer”)Composed of 8–10 layers ofkeratinocytes bound togetherby desmosomesBeginkeratinproductionWater repellant proteinContainsdendritic(Langerhans) cellsPart of immuneresponseOnly look spiny on histology
Epidermis3.Stratum granulosum(“grainy layer”)Composed of 3–5 layers ofkeratinocytesContinue producingkeratinCells grow thinner and flatterCell membranes thicken andbecome less permeable
Epidermis4.Stratumlucidum(“clearlayer”)Found only in thick skinSeparates stratum corneumfrom underlying layersFlattened, densely packeddead cells filled withkeratin
Epidermis5.Stratum corneum(cornu, horn)Outermost, protective regionwith 15–30 layers ofkeratinized cells (filled withkeratin)Dead cells still tightlyconnected by desmosomesWater resistant, notwaterproofLose water throughinsensibleperspiration(unable to see or feel) andsensibleperspiration(sweat)
EpidermisThin skinCovers most of body surfaceFour strataDoes not contain StratumLucidumThick skinFound on palms of hands andsoles of feetFive strataContains Stratum Lucidum
Skin Color
Skin ColorMelaninBrown, yellow-brown, or blackpigmentProduced bymelanocytesinstratum basaleDarker = greater melaninproductionProtects skin cell DNAIncreases production with UVexposure
Skin ColorCaroteneOrange-yellow pigmentDietaryRed, orange, yellow, and greenvegetablesα/β-Carotene becomes Vitamin AXanthophylls provide color &photosynthesisResponsible for fall leaf colorsGrune, T. (2010) β-Carotene is an important vitamin A source for humans.The Journal ofNutrtion. 140(2): 2268S-2285S.
Skin ColorHemoglobin(blood protein)

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Term
Fall
Professor
NoProfessor
Tags
Stratum lucidum, Exocrine Glands, Sudoriferous glands, Body s first line

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