Integumentary system

SKIN - ANATOMY AND PHYSIOLOGY

2. INTRODUCTION
•Theorgansoftheintegumentarysystem
includetheskinanditsaccessorystructures
includinghair,nails,andglands,aswellas
bloodvessels,musclesandnerves
•Dermatologyisthemedicalspecialtyfor
thediagnosisandtreatmentofdisordersof
theintegumentarysystem.

3. STRUCTURE OF THE SKIN
•Theskin(cutaneousmembrane)covers
thebodyandisthelargestorganofthebody
bysurfaceareaandweight
•Itsareaisabout2squaremeters(22square
feet)andweighs4.5-5kg(10-11lb),about
7%ofbodyweight
•Itis0.5–4mmthick,thinnestonthe
eyelids,thickestontheheels;theaverage
thicknessis1–2mm

5. STRUCTURE OF THE SKIN
•Itconsistsoftwomajorlayers:
•outer,thinnerlayercalledtheepidermis,
consistsofepithelialtissue(seevideo)
•inner,thickerlayercalledthedermis
•Beneaththedermisisasubcutaneous
(subQ)layer(alsocalledhypodermis)
whichattachestheskintotheunderlying
tissuesandorgans.

6. EPIDERMIS
•Covers,protects,andwaterproofs.
•Containsfourmainlayers:
•Stratumcorneum:Keratinizedlayer.Preventsloss
orentryofwater;protectsagainstpathogensand
chemicals.
•Stratumlucidum:Foundonlyonpalmsofhands
andsolesoffeet;protectsagainstUVsunraysto
preventsunburn.
•Stratumgranulosum
•Stratumgerminativum:Theinnermostlayerof
epidermis,istheonlylayerthatundergoescell
division&containsmelanin&keratin-formingcells.

8. •Theepidermishasanumberofimportant
characteristics:
•theepidermisiscomposedofkeratinizedstratified
squamousepithelium
•itcontainsfourmajortypesofcells:
•Keratinocytes(90%ofthecells)producekeratinwhichisa
toughfibrousproteinthatprovidesprotection.
•Melanocytes:whichproducethepigmentmelaninthat
protectsagainstdamagebyultravioletradiation
•Langerhanscells:involvedinimmuneresponses,arise
fromredbonemarrow
•Merkelcells:whichfunctioninthesensationoftouchalong
withtheadjacenttactilediscs

9. TYPES OF CELLS IN
THE EPIDERMIS

11. •Theepidermis,hair,nail,dentalenamel,&
hornytissuesarecomposedofkeratin.
•Itisreplacedevery3-4weeks.
•Skincolordependson:
1.Theamountofmelanin&carotene"yellow
pigment"containedintheskin
2.Thevolumeofbloodcontaininghemoglobin
3.Theoxygen-bindingpigmentthatcirculatesin
thedermis.

12. DERMIS
•Thedermishasseveralimportant
characteristics:
•iscomposedofconnectivetissuecontaining
collagenandelasticfibers
•containstwolayers
•theouterpapillaryregionconsistsofareolar
connectivetissuecontainingthincollagenandelastic
fibers,dermalpapillae(includingcapillaryloops),
corpusclesoftouchandfreenerveendings

13. •Thedeeperreticularregionconsistsof
denseirregularconnectivetissue
containingcollagenandelasticfibers
adiposecells,hairfollicles,nerves,
sebaceous(oil)glands,and
sudoriferous(sweat)glands
•Striaeorstretchmarkscanappearifthe
skinisstretchedtoomuch

15. •SweatGlands(Sudoriferous):Mostnumerouson
palmsofhandsandsolesoffeet.
•Twotypesareeccrineandapocrineglands.
•EccrineGlands:Respondtoexternal
temperatureandpsychologicalstress.
•Foundovermostofbodybutmostnumerouson
palmsofhandsandsolesoffeet;secretesweat,which
helpsregulatebodytemperatureand,toalesser
degree,excreteswastessuchasurea.

17. •ApocrineorOdoriferousGlands:
•Foundinaxillaandgenitalarea.
•Respondtostress;secretepheromones,a
substancewithabarelyperceptibleodor;when
apocrinesecretionsreactwithbacteria,body
odorresults.
•Ceruminousglandsareatypeofapocrine
glandfoundintheexternalearcanal.
•Theysecretecerumen,whichpreventsdrying
oftheeardrumandtrapsforeignsubstances.

18. •SebaceousGlands:Producesebum,which
lubricatesandprotectsskinandhair.
•Cholesterol:ConvertstovitaminDwhen
exposedtoUVlights.
•Arterioles:Dilatewhenhottoincreaseheat
lossandconstrictwhencoldtoconserve
heat.
•Constrictinresponsetostressfulsituationstoshunt
bloodtovitalorgans.

20. •Linesofcleavage-“tensionlines”inthe
skinindicatethepredominantdirectionof
underlyingcollagenfibers
•Epidermalridgesreflectcontoursofthe
underlyingdermalpapillaeandformthe
basisforfingerprints(andfootprints);their
functionistoincreasefirmnessofgripby
increasingfriction.
•Dermatoglyphics-thestudyofthepattern
ofepidermalridges

22. CLEAVAGE (TENSION) LINES AND STRIAE
•Cleavage(tension)lines:
elastinandcollagenfibers
orientedinsomedirections
morethaninothers
•Importantinsurgery
•Ifincisionparallelto
lines,thereisless
gapping,fasterhealing,
lessscartissue
•Ifskinisoverstretched,
striae(stretchmarks)occur

23. HYPODERMIS / SUBCUTANEOUS
•ConnectiveTissue:Connectsskin
tomuscles;containswhiteblood
cells.
•AdiposeTissue:Containsstored
energy,cushionsbonyprominences,
providesinsulation.

24. ACCESSORY STRUCTURES OF THE
SKIN
•includehair,andnails
•Hairs(pili)haveanumberof
importantfunctions:
•protection
•reductionofheatloss
•sensinglighttouch

25. THE HAIR
Thehairisalsomadeupofkeratinizedcells.
1.Vellus,whichisshort,pale,andfinehair,is
locatedoverallofthebody.
2.Terminalhairs,whicharedarkandcoarse,are
foundonthescalp,brows,and,afterpuberty,on
thelegs,axillae,andperineum.

26. •Hairiscomposedofdead,
keratinizedepidermalcells
•Hairconsistsof:
•shaftwhichmostlyprojectsabovethe
surfaceoftheskin
•rootwhichpenetratesintothedermis
•hairfollicle
•epithelialrootsheath–(downward
continuationoftheepidermis)
•dermalrootsheath

30. NAILS
Nailsarecomposedofhard,keratinized
epidermalcellslocatedoverthedorsal
surfacesoftheendsoffingersandtoes
Eachnailconsistsof:
freeedge
transparentnailbody(plate)withawhitish
lunulaatitsbase
nailrootembeddedinafoldofskin

31. NAILS

32. TYPES OF SKIN
Therearetwomajortypesofskin:
thin(hairy)skincoversallbody
regionsexceptthepalms,palmar
surfacesofdigits,andsoles
thick(hairless)skincoversthepalms,
palmarsurfacesofdigits,andsoles

33. AGING EFFECTS
•wrinkling
•decreaseofskin’simmuneresponsiveness
•dehydrationandcrackingoftheskin
•decreasedsweatproduction
•decreasednumbersoffunctionalmelanocytesresulting
ingrayhairandatypicalskinpigmentation
•lossofsubcutaneousfat
•ageneraldecreaseinskinthickness
•anincreasedsusceptibilitytopathologicalconditions
Growthofhairandnailsdecreases;nailsmayalso
becomemorebrittlewithage.

36. FUNCTIONS OF THE SKIN
regulationofbodytemperature
bloodreservoir
protection
cutaneoussensations
excretionandabsorption
synthesisofvitaminD

43. RELATIONSHIP OF THE
INTEGUMENTARY SYSTEM TO OTHER
SYSTEMS

44. •ENDOCRINE
•Thyroidaffectsgrowthandtextureofskin,
hairandnails.
•Hormonesstimulatesebaceousglands.
•Sexhormonesaffecthairgrowthand
distribution,fatandsubcutaneoustissue
distributionandactivityofapocrinesweat
glands.
•Adrenalhormonesaffectdermalblood
supplyandmobilizelipidsfromadipocytes.

45. URINARY
Kidneys remove waste and maintain normal
pH.
Skin helps eliminate water and waste.
Skin prevents excess fluid loss.
DIGESTIVE
Skin synthesizes vitamin D for calcium and
phosphorous absorption.
Supplies nutrients while skin stores lipids.

46. •CARDIOVASCULAR
•Mastcellstimulationproduceslocalizedchangesin
bloodflowandcapillarypermeability.
•CVsystemprovidesnutrientsandremoveswastes.
•Delivershormonesandlymphocytes.
•Providesheatforskintemperature.
•SKELETAL
•SkinsynthesizesvitaminDneededforcalciumand
phosphorusabsorption.
•Skeletalsystemprovidesaframeworkforskin.

47. LYMPHATIC/IMMUNE
Skinisfirstlineofdefense.
Langerhancellsandmacrophagesresistinfection.
Mastcellstriggerinflammatoryresponses.
Lymphaticsystemprotectsskinbysendingmore
macrophagesandlymphocyteswhenneeded.
RESPIRATORY
Providesoxygentoandremovescarbondioxidefrom
integumentarysystem.
Colorofskinandnailscanreflectchangesin
respiratorysystem.

48. •MUSCULAR
•SkinsynthesizesvitaminDneededforcalcium
absorptionformusclecontraction.
•Givesshapetoandsupportsskin.
•Contractionoffacialmusclesallowscommunication
throughexpressions.
•NEUROLOGICAL
•Sensoryreceptorsindermistotouch,temperature,
pressure,vibrationandpain.
•Providescommunicationwithexternalenvironment.
•Controlsbloodflowandsweatingthrough
thermoregulation.

49. SEASONAL SKIN DISORDERS
•Spring:Chickenpox,Acneflare-ups
•Summer:Contactdermatitis,Tinea,
Candida,Impetigo,Insectbites
•Fall:Senilepruritus/winteritch,Pityriasis
rosea,Urticaria,Acneflare-ups
•Winter:Contactdermatitisofhands,Senile
pruritus/winteritch,Psoriasis,Eczema
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