8/3/2019 Derma - Skin

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DermatologySkinandIntegumentarySystem

kirstie

SkinandtheIntegumentarySystem

Composedofseveraltissues Maintainshomeostasis Protectivecovering Retardswaterloss Regulatesbodytemperature Housessensoryreceptors Containsimmunesystemcells Synthesizeschemicals,includingVitaminD Excretessmallamountsofwaste

LayersofSkin

1. Epidermis-stratumbasale

-keratinocytes=90%epidermalcells

-melanocytes=8%epidermalcells

-subdividedintolayersofstratifiedsquamous

epithelium-lacksbloodvessels

-keratinized

-thickestonpalmsandsoles(0.81.4mm)

-melanocytesprovidemelanin

-restsonbasementmembrane

EpidermalDifferentiation

- Increaseincellsizeandshape- Appearanceofnewcellularorganelles- Changefromageneralizedcellularmetabolism

toamorefocusedmetabolism- Alterationinthepropertiesoftheplasma

membranecellsurfaceantigenandreceptor

- Dehydrationofcellularorganelles- Terminallydiffkeratinocyte(keratinfilaments,

matrixproteins,proteinreinforcedmembrane

withsurfaceassociatedlipids

Nonkeratinocyteinepidermis

Melanocytepigmentproducingcell Merkelcellmechanoreceptor Langerhanscell

Melanocyte

- Dendriticpigmentsynthesizingcellderivedfromtheneuralcrest

- HISTO:palestainingcytoplasmwithovoidnucleusandtheintrinsiccolorofpigment

containingmelanosomes

- (+)vimectin,(-)keratinfilaments

- Dividesataratekeepingpacewithkeratinocyteturnover

- EPIDERMALMELANINUNIT(36basalandsuprabasalkeratinocytecoexistwithone

melanocyte)

Merkelcell- slowadaptingtype1mechanoreceptor- locatedinsitesofhightactilesensitivitye.g.

digits

- nonkeratinocytelocatedatthebasallayeroftheepidermis

- HISTO:palestainingcytoplasm,nucleusislobulatedandmarginsofcellproject

cytoplasmicspinestowardkeratinocytes

- Sites:hairyandglaborousskinofdigits,lips,regionsoftheoralcavity,outerrootsheathof

hairfollicle

Langerhanscell

- nonkeratinocytedistributedinbasal,spinousandgranularlayerswithpreferenceforthe

suprabasalposition

- HISTO:palestainingandhaveconvolutednuclei

- Electronmicroscopy:withdispersedvimectinfilamentsandsmallrodorracketshaped

structurescalledbirbeckgranules

- Responsibleforrecognition,uptake,processingandpresentationofsolubleantigensandhaptenstosensitizedTlymphocytes

*Basementmembrane

-isanchoredtothedermisbyshortfibrilsand

separatesthesetwolayersofskin

2. Dermis-madeupofconnectivetissue,epithelialtissue,

smoothmuscletissue,nervoustissue,andblood

-onaverage1.02.0mmthick

-dermalpapillae-bindsepidermistounderlyingtissues

-irregulardenseconnectivetissue

-musclecells

-nervecellprocesses

-bloodvessels

-hairfollicles

-glands

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DermatologySkinandIntegumentarySystem

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a. Papillaryregioni. superficialdermiswithpapillaeii. areolarconnectivetissue

b. Reticularregioni. deeperfour/fifthsofdermisii. denseirregularconnective

tissueiii. collagenandelasticfibersiv. contains:bloodvessels,nerves,

glandsandhairfollicles

SweatorSudoriferousGlands

widespreadinskin deeperdermisorhypodermis eccrineglandstypesofmerocrineglandthat

secretefluid(sweat)productreleasedthrough

thecellmembrane

aprocrinesweat,ceruminous(wax),andmammary(milk)glandstypesofapocrine

glandsthatsecretecellularproductandportion

ofthefreeandsofcells

SebaceousGlands

usuallyassociatedwithhairfollicles holocrineglandsdisintegratingcellandits

contentsforthesecretion

secretesebum absentonpalmsandsoles

HairFollicles

epidermalcells tube-likedepression extendsintodermis hairroot hairshaft hairpapilla deadepidermalcells melanin arrectorpilimuscle

Haircycleo Anagengrowingphase

80-90%ofscalphair,3-4yearsinhumanscalp

o Telogenphase restingphase Averageof3months

o Catagenphasetransitoryphase Clubhair,averageof3weeks

3segmentso infundibularportiono isthmuso inferiorormatrix

3. Subcutaneouslayer Hypodermis Looseconnectivetissue Adiposetissue Insulates Majorbloodvessels

SkinColor

GeneticFactors

Varyingamountsofmelanin Varyingsizeofmelaningranules Albinoslackmelanin

PhysiologicalFactors

Dilationofdermalbloodvessels Constrictionofdermalbloodvessels Carotene Jaundice

EnvironmentalFactors

Sunlight UVlightfromsunlamps X-rays

Mechanicsofpigmenttransfer

Fusionandbreakdownofplasmamembraneofbothmelanocyteandkeratinocyteestablishing

acommunicationbetweenthecells

Phagocytosisofmelanosomescontainingthedendriticprocessesbythekeratinocytecalled

apoptosis

*Allpeoplehavethesamenumberofmelanocytesin

theirskin

2typesofmelanin

Eumelaninbrownorblackcolor,ellipticalinshape

Pheomelaninredoryellow.Withlessregularshape

*sizeofmelanosomesinblackskinarelargerthanin

lightskinindividuals

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DermatologySkinandIntegumentarySystem

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Nails

Protectivecoverings Nailplate Nailbed Lunula

LifeSpanChanges Scalyskin Agespots Dermisbecomesreduced Lossoffat Wrinkles Sagging Sebaceousglandssecretlessoil Melaninproductionslows Hairthins Numberofhairfolliclesdecrease Impairednailgrowth Sensoryreceptorsdecline Inabilitytocontrolbodytemperature LessvitaminDproduction

SkinProblems

Hairfollicleo Alopeciaareata,telogeneffluvium,

androgeneticalopecia

Sebaceousglando Acnevulgaris,sebaceouscyst,

steatocystomamultiplex Apocrinegland

o Hidradenitissuppurative,Foxfordycesdisease

Sweatglando Hyperhidrosis,bromhidrosis,

anhidrosis,chromhidrosis

o Syringoma Keratinocyte

o Psoriasis Melanocyte

o Vitiligo,Albinism,Postinflammatoryhyper/hypopigmentation

ClinicalApplication

AcneVulgaris

Mostcommonskindisorder Sebumandepithelialcellsclogglands

Produceswhiteheadsandblackheads

(comedones)

Anaerobicbacteriatriggerinflammation(pimple)

Largelyhormonallyinduced Androgensstimulatesebumproduction Treatmentsincludeantibiotics,topicalcreams,

birthcontrolpills

*pleaserefertotheslidesforthepictures

AsteatoticeczemaSebaceoushyperplasia

Psoriasis

ChronicBullousdiseaseinchildren(epidermodermal

junction)

VitiligoGeneralizedtype

Postinflamhypopigmentation(melanocytes)

Pigmentaryproblems(melanocytes)

Melasma(melanocytes)

Syringoma(eccrineglands)

Steatocytomamultiplex(sebaceousglands)

Foxfordycesdisease(apocrineglands)

Alopeciaareata(hairfollicle)

Androgenicalopecia(hairfollicle)

Femaleandrogenicalopecia

OnycholysisinPsoriasis

Onychomycosis

XerodermaPigmentosumextremefrecklingandskin

cancerduetolackofDNArepairenzymes

Squamousandbasalcellcarcinomaderivedfrom

epithelialtissue

Malignantmelanomaderivedfrommelanocytes