Integumentary SystemSlide 4.8Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsSkin (cutaneous membrane)Skin derivativesSweat glandsOil glandsHairsNails

Skin FunctionsSlide 4.9aCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsProtects deeper tissues from:Mechanical damageChemical damageBacterial damageThermal damageUltraviolet radiationDesiccation

Skin FunctionsSlide 4.9bCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsAids in heat regulationAids in excretion of urea and uric acidSynthesizes vitamin D

Skin StructureSlide 4.10aEpidermis outer layerStratified squamous epitheliumOften keratinized (hardened by keratin)

Layer of EpidermisSlide 4.11aCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsStratum basaleCells undergoing mitosisLies next to dermisStratum spinosumStratum granulosum

Layer of EpidermisSlide 4.11bStratum lucidumOccurs only in thick skinStratum corneumShingle-like dead cells

MelaninSlide 4.12Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsPigment (melanin) produced by melanocytesColor is yellow to brown to blackMelanocytes are mostly in the stratum basaleAmount of melanin produced depends upon genetic and exposure to sunlight

Skin Color DeterminantsSlide 4.14MelaninYellow, brown or black pigmentsCaroteneOrange-yellow pigment from some vegetablesHemoglobinRed coloring from blood cells in dermis capillariesOxygen content determines the extent of red coloringCyanosis - Low oxygen content creates a bluish appearance

MELANINHow Sun Effects Melanin

DermisDense connective tissue

DermisSlide 4.13aCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsTwo layersPapillary layerProjections called dermal papillaePain receptorsCapillary loopsReticular layerBlood vesselsGlandsNerve receptors

FINGERPRINTS

WH0RL

ARCH

LOOPArise from the interaction of an individuals genes and the developmental environment in the uterus. Genes determine general characteristics of patterns that are used for fingerprint classification. As the skin on the fingertip differentiates, it expresses these general characteristics. This skin is also in contact with the amniotic fluid in the uterus and other parts of the fetus and the uterus, and their position in relation to uterus and the fetal body changes as the fetus moves on its own and in response to positional changes of the mother. The area around growing cells on the fingertip is in flux, and is always slightly different from hand to hand and finger to finger. Their effect is amplified by the differentiating cells and produces the larger differences that enable the fingerprints of even identical twins to be differentiated.

Skin StructureSlide 4.10bDeep to dermis is the hypodermisNot part of the skinAnchors skin to underlying organsComposed mostly of adipose tissue

Skin StructureSlide 4.13bCopyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFigure 4.4

Appendages of the SkinSlide 4.15Sebaceous glandsProduce oilLubricant for skinKills bacteriaMost with ducts that empty into hair folliclesGlands are activated at puberty

Appendages of the SkinSlide 4.16Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsSweat glandsWidely distributed in skinTwo typesEccrineApocrine

Eccrine sweat glandOpen via duct to pore on skin surface

Apocrine sweat glandDucts empty into hair follicles

Sweat and Its FunctionSlide 4.17Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCompositionMostly waterSome metabolic wasteFatty acids and proteins (apocrine only)FunctionHelps dissipate excess heatExcretes waste productsAcidic nature inhibits bacteria growthOdor is from associated bacteria

Appendages of the SkinSlide 4.18Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsHairProduced by hair bulbConsists of hard keratinized epithelial cellsMelanocytes provide pigment for hair colorFigure 4.7c

HAIR FOLLICLE

Hair AnatomySlide 4.19Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsCentral medullaCortex surrounds medullaCuticle on outside of cortexMost heavily keratinizedFigure 4.7b

Asian, Caucasian, AfricanIn this cross-section of a hair root, the dark cortex and medulla are surrounded by the interlocked cuticles, Huxley's and Henle's layers, the outer epithelial root sheath, a deeply stained basement membrane and, finally, the well-vascularized connective tissue sheath.

Associated Hair StructuresSlide 4.20Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsHair follicleDermal and epidermal sheath surround hair rootArrector pilliSmooth muscleSebaceous glandSweat glandFigure 4.7a

Appendages of the SkinSlide 4.21Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsNailsScale-like modifications of the epidermisHeavily keratinizedStratum basale extends beneath the nail bedResponsible for growthLack of pigment makes them colorless

Nail StructuresSlide 4.22Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsFree edgeBodyRoot of nailEponychium proximal nail fold that projects onto the nail bodyFigure 4.9

Skin Homeostatic ImbalancesSlide 4.23Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsInfectionsAthletes footCaused by fungal infectionBoils and carbunclesCaused by bacterial infectionCold soresCaused by virus

Skin Homeostatic ImbalancesSlide 4.24Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsInfections and allergiesContact dermatitisExposures cause allergic reactionImpetigoCaused by bacterial infectionPsoriasisCause is unknownTriggered by trauma, infection, stress

Skin Homeostatic ImbalancesSlide 4.25Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsBurnsTissue damage and cell death caused by heat, electricity, UV radiation, or chemicalsAssociated dangersDehydrationElectrolyte imbalanceCirculatory shock

Rules of NinesSlide 4.26Copyright 2003 Pearson Education, Inc. publishing as Benjamin CummingsWay to determine the extent of burnsBody is divided into 11 areas for quick estimationEach area represents about 9%

Severity of BurnsFirst-degree burnsOnly epidermis is damagedSkin is red and swollenSecond degree burnsEpidermis and upper dermis are damagedSkin is red with blistersThird-degree burnsDestroys entire skin layerBurn is gray-white or black