Integumentary System

Integumentary SystemIntegumentary System

Introduction to the IntegumentIntroduction to the Integument The EpidermisThe Epidermis The DermisThe Dermis The Subcutaneous LayerThe Subcutaneous Layer Accessory StructuresAccessory Structures Local Control of Integumentary Local Control of Integumentary

FunctionFunction Aging and the Integumentary Aging and the Integumentary

SystemSystem

IntroductionIntroduction

• The IntegumentThe Integument:: Large, highly complex organ (?)Large, highly complex organ (?) Structurally integrated organ Structurally integrated organ

system (?)system (?)• FactoidsFactoids::

16% of body weight16% of body weight 1.5 – 2.0 m1.5 – 2.0 m2 2 surface areasurface area Affected by other body systems Affected by other body systems Affected by emotional stateAffected by emotional state

Learning ObjectivesLearning Objectives

• IntegumentIntegument:: List the major components of the List the major components of the

integumentary systemintegumentary system Discuss the tissue types of the Discuss the tissue types of the

integumentintegument

• FunctionsFunctions ofof thethe IntegumentIntegument:: Describe six functions of the Describe six functions of the

integumentintegument

Integumentary System:Integumentary System:Major ComponentsMajor Components

• Cutaneous MembraneCutaneous Membrane::– EpidermisEpidermis

• stratified squamous epitheliumstratified squamous epithelium• basement membranebasement membrane

– DermisDermis • loose connective tissueloose connective tissue• dense irregular connective tissuedense irregular connective tissue

• Accessory StructuresAccessory Structures::– hairhair– glandsglands– nailsnails

Integumentary Integumentary ComponentsComponents

• EpidermisEpidermis::

superficial epitheliumsuperficial epithelium

• DermisDermis::

connective tissue connective tissue

accessory structuresaccessory structures

• Subcutaneous LayerSubcutaneous Layer::

connective tissueconnective tissue

superficial fasciasuperficial fascia

Integumentary Integumentary FunctionFunction

• ProtectionProtection – of underlying tissues & – of underlying tissues & organsorgans

• ExcretionExcretion – of salts, H – of salts, H22O, & wasteO, & waste• MaintenanceMaintenance – of normal body – of normal body

temperaturetemperature• SynthesisSynthesis – of vitamin D – of vitamin D33

• StorageStorage – of nutrients (lipids, protein) – of nutrients (lipids, protein)• DetectionDetection – of touch, pressure, – of touch, pressure,

temperature change, & paintemperature change, & pain

The EpidermisThe Epidermis

• Layers of the EpidermisLayers of the Epidermis• Skin ColorSkin Color

• The Epidermis & Vitamin DThe Epidermis & Vitamin D33

• Epidermal Growth FactorEpidermal Growth Factor


• EpidermalEpidermal LayersLayers:: List & describe the layers of the List & describe the layers of the

epidermis in order from deepest to epidermis in order from deepest to most superficialmost superficial

Identify the dominant proteins of Identify the dominant proteins of epidermal cells epidermal cells

Distinguish between “thin” & “thick” Distinguish between “thin” & “thick” skinskin

EpidermisEpidermis

Layers of the Layers of the EpidermisEpidermis

• Stratum Stratum GerminativumGerminativum (a.k.a., (a.k.a., stratum basale)stratum basale)

• Stratum Stratum SpinosumSpinosum• Stratum Stratum GranulosumGranulosum• Stratum Stratum LucidumLucidum (in specific loci) (in specific loci)• Stratum Stratum CorneumCorneum

NoteNote:: order from deepest to most superficial order from deepest to most superficial

Stratified Squamous Stratified Squamous EpitheliumEpithelium

Stratum Stratum GerminativumGerminativum

• “ “sprouting layer” sprouting layer” • deepestdeepest layer layer• 11 layer of layer of cuboidalcuboidal stem cellsstem cells• firmly attached to firmly attached to basement basement

membranemembrane• epidermal ridges extend into epidermal ridges extend into

dermisdermis• melanocytesmelanocytes present present

epidermal ridgeepidermal ridge

Stratum Stratum SpinosumSpinosum

• “ “spiny layer” spiny layer” • above str. germinativumabove str. germinativum• 8-108-10 layers of layers of roundedrounded

keratinocyteskeratinocytes bound together by bound together by desmosomesdesmosomes

• LangerhansLangerhans cells present cells present

Stratum Stratum GranulosumGranulosum

• “ “granular layer” granular layer” • above str. spinosumabove str. spinosum• 3-53-5 layers of layers of ovoidovoid keratinocyteskeratinocytes

packed with keratin-filled granulespacked with keratin-filled granules• nuclei & other organelles begin to nuclei & other organelles begin to

disintegratedisintegrate• cell membranes become cell membranes become

impermeableimpermeable

Stratum Stratum LucidumLucidum

• • “ “glassy layer” glassy layer” • above str. granulosumabove str. granulosum• 2-32-3 layers of layers of flattened flattened

keratinocyteskeratinocytes• cells very densely packed togethercells very densely packed together• occurs only on the palms of the occurs only on the palms of the

hands & soles of the feethands & soles of the feet

Stratum Stratum CorneumCorneum

• • “ “horny layer”horny layer”• most most superficialsuperficial layer layer• 15-3015-30 layers of layers of flatflat keratinocyteskeratinocytes

cells firmly connected by cells firmly connected by desmosomesdesmosomes

• packed with keratinpacked with keratin• relatively relatively drydry & & water resistantwater resistant• Cells are deadCells are dead

Thin Skin -v- Thick SkinThin Skin -v- Thick Skin

Thin Skin -v- Thick SkinThin Skin -v- Thick Skin

Skin ColorSkin Color

• Pigment ComponentsPigment Components• Non-pigment ComponentNon-pigment Component• Pigment FunctionsPigment Functions• Melanocyte Structure & FunctionMelanocyte Structure & Function• Skin Color DifferencesSkin Color Differences


• SkinSkin ColorColor:: Discuss the factors that contribute to Discuss the factors that contribute to

skin colorationskin coloration Name the sources of skin pigmentsName the sources of skin pigments Discuss the effects of ultraviolet Discuss the effects of ultraviolet

radiation on the skin and the radiation on the skin and the protective role played by melanocytesprotective role played by melanocytes


• Pigment ComponentsPigment Components:: MelaninMelanin

brown – yellow-brown – black pigmentbrown – yellow-brown – black pigment sourcesource – melanocytes – melanocytes

CaroteneCarotene orange-yellow pigmentorange-yellow pigment accumulates in epidermal and adipose accumulates in epidermal and adipose

tissues of skin from tissues of skin from sourcesource – plants, esp. orange & yellow – plants, esp. orange & yellow

colored fruits & vegetablescolored fruits & vegetables


• Non-pigment ComponentNon-pigment Component:: HemoglobinHemoglobin

dermal circulationdermal circulation reddish tint due to oxyhemoglobinreddish tint due to oxyhemoglobin cyanosiscyanosis - bluish tint due to non- - bluish tint due to non-

oxygenated hemoglobinoxygenated hemoglobin


• Pigment FunctionsPigment Functions:: MelaninMelanin

protection from UV radiationprotection from UV radiation melanosomes concentrate around cell melanosomes concentrate around cell

nucleinuclei CaroteneCarotene

conversion to conversion to vitamin Avitamin A (1) normal maintenance of epithelia(1) normal maintenance of epithelia

(2) synthesis of photoreceptor-(2) synthesis of photoreceptor-receptor pigments in eyereceptor pigments in eye

MelanocytesMelanocytes

• Melanocyte StructureMelanocyte Structure Long processes weave from str. Long processes weave from str.

germinativum into str. spinosum & germinativum into str. spinosum & granulosumgranulosum

• Melanocyte FunctionMelanocyte Function Packages melanin into vesicles - Packages melanin into vesicles -

melanosomesmelanosomes MelanosomesMelanosomes transferred to keratinocytes transferred to keratinocytes Melanin absorbs potentially harmful UV Melanin absorbs potentially harmful UV

radiationradiation


• Differences in skin colorDifferences in skin color:: Number of melanocytes is Number of melanocytes is

equivalent in all races & ethnic equivalent in all races & ethnic groupsgroups

Skin tones due toSkin tones due to amount of melaninamount of melanin produced by produced by

melanocytesmelanocytes melanin colormelanin color persistence of melanosomespersistence of melanosomes in upper in upper

layers of the epidermislayers of the epidermis

Vitamin DVitamin D33 & Epidermal & Epidermal Growth FactorGrowth Factor

• Vitamin DVitamin D33 Structure & Production Structure & Production

• Vitamin DVitamin D33 & Calcitriol Function & Calcitriol Function

• EGF Structure & FunctionEGF Structure & Function


• VitaminVitamin DD33:: Discuss the production & importance Discuss the production & importance

of vitamin Dof vitamin D3 3

• EpidermalEpidermal GrowthGrowth FactorFactor:: Explain how EGF contributes to Explain how EGF contributes to

maintenance of the integumentmaintenance of the integument

The Epidermis & Vitamin The Epidermis & Vitamin DD33

• Vitamin DVitamin D33: :

a.k.a., cholecalciferola.k.a., cholecalciferol steroidsteroid converted to converted to calcitriolcalcitriol calcitriol promotes Cacalcitriol promotes Ca2+2+ & PO & PO44

3-3- uptake by small intestineuptake by small intestine

essential for essential for normal bone growth normal bone growth & maintenance& maintenance

The Epidermis & Vitamin The Epidermis & Vitamin DD33

• ProcessProcess::(1)(1) UV light converts cholesterol-related UV light converts cholesterol-related

steroid to vitamin Dsteroid to vitamin D33

(2)(2) vitamin Dvitamin D3 3 travels in circulation to liver travels in circulation to liver where it is converted to intermediatewhere it is converted to intermediate

(3)(3) Intermediate travels to kidney where it Intermediate travels to kidney where it is converted to calcitriolis converted to calcitriol

(4)(4) calcitriol promotes intestinal cell calcitriol promotes intestinal cell permeability to calcium and phosphatepermeability to calcium and phosphate

Epidermal Growth FactorEpidermal Growth Factor

• EGPEGP: : peptide hormonepeptide hormone produced by salivary glands & produced by salivary glands &

duodenum of small intestineduodenum of small intestine widespread effects on epitheliawidespread effects on epithelia specific effects on epidermisspecific effects on epidermis

Epidermal Growth FactorEpidermal Growth Factor

• Effects on EpidermisEffects on Epidermis: : Promotes Promotes cell divisioncell division in str. in str.

germinativum & spinosumgerminativum & spinosum Accelerates Accelerates keratin productionkeratin production Stimulates epidermal development Stimulates epidermal development

& & epidermal repairepidermal repair Stimulates synthesis & Stimulates synthesis & secretion secretion

by epidermal glandsby epidermal glands

Physics of Electromagnetic RPhysics of Electromagnetic Radiationadiation

• To View Video:To View Video:– Move mouse cursor over slide title-linkMove mouse cursor over slide title-link– When hand appears, click onceWhen hand appears, click once

• ASX Video plays about 30 minASX Video plays about 30 min

The DermisThe Dermis

• Dermal OrganizationDermal Organization

• Dermal CirculationDermal Circulation

• Dermal InnervationDermal Innervation


• DermalDermal OrganizationOrganization:: List the layers of the dermis from List the layers of the dermis from

most superficial to deepestmost superficial to deepest Distinguish between the structure Distinguish between the structure

and function of the dermal layersand function of the dermal layers• DermalDermal CirculationCirculation & Innervation& Innervation::

Name sensory structures of the Name sensory structures of the dermis and describe their functionsdermis and describe their functions

Dermal OrganizationDermal Organization

Layers of the DermisLayers of the Dermis

• Papillary LayerPapillary Layer

• Reticular LayerReticular Layer

NoteNote:: order from most superficial to deepest order from most superficial to deepest

Papillary LayerPapillary Layer

• loose connective tissueloose connective tissue• capillaries – capillaries – papillary plexuspapillary plexus• sensory nerve endings sensory nerve endings • dermal papillaedermal papillae – – ↑↑ surface area to surface area to

bind overlying epidermis to dermisbind overlying epidermis to dermis

Papillary Layer Papillary Layer CharacteristicsCharacteristics

Reticular Layer Reticular Layer CharacteristicsCharacteristics

• dense irregular connective dense irregular connective tissuetissue

• bound to papillary layer above bound to papillary layer above & subcutaneous layer below by & subcutaneous layer below by bundles of bundles of collagencollagen fibers fibers

• capillaries – capillaries – cutaneous plexuscutaneous plexus


• extracellular protein fibersextracellular protein fibers collagencollagen – strength – strength elastinelastin – permits stretching – permits stretching

• all cells of connective tissue proper: all cells of connective tissue proper: adipocytes, fibroblasts, macrophages, adipocytes, fibroblasts, macrophages, etcetc

• accessory organsaccessory organs of epidermal origin of epidermal origin extend into dermis: hair follicles, sweat extend into dermis: hair follicles, sweat & sebaceous glands& sebaceous glands

• contains blood vessels, lymph vessels & contains blood vessels, lymph vessels & nervesnervesdense irregular connective tissuedense irregular connective tissue

loose connective tissue properloose connective tissue proper

Dermal Reticular LayerDermal Reticular Layer

blood vesselblood vessel

collagen collagen fiber fiber

bundles bundles (c.s.)(c.s.)

loose loose connective connective

tissuetissue

smooth smooth musclemuscle


Papillary Papillary LayerLayer

Reticular Reticular LayerLayer

Papillary PlexusPapillary Plexus

Cutaneous PlexusCutaneous Plexus

• Wrinkles - reduced elastin:Wrinkles - reduced elastin: agingaging dehydrationdehydration hormoneshormones UV radiationUV radiation

• Stretch marks – damaged elastinStretch marks – damaged elastin pregnancypregnancy weight loss after weight gainweight loss after weight gain

Wrinkles & Wrinkles & Stretch MarksStretch Marks

Lines of CleavageLines of Cleavage

• due to due to parallel arrangements of parallel arrangements of elastin & collagen fiberselastin & collagen fibers in areas of in areas of the skinthe skin

• Function Function – – to resist applied forces to resist applied forces from muscle contraction, joint from muscle contraction, joint movement, etcmovement, etc

• a cut parallel to cleavage lines will a cut parallel to cleavage lines will remain closedremain closed; a cut perpendicular ; a cut perpendicular will remain open due to elastic fiber will remain open due to elastic fiber recoilrecoil

Typical incision for Typical incision for appendectomyappendectomy

Skin InnervationSkin Innervation

• Nervous System ControlNervous System Control:: blood flowblood flow gland secretion ratesgland secretion rates

• Sensory FunctionSensory Function:: root hair plexusesroot hair plexuses – hair displacement by wind, – hair displacement by wind,

contactcontact Pacinian corpusclesPacinian corpuscles – deep pressure – deep pressure Merkel’s discsMerkel’s discs – fine touch; light pressure – fine touch; light pressure Ruffini corpusclesRuffini corpuscles – (in deep dermis) heavy – (in deep dermis) heavy

pressure; distortion of skinpressure; distortion of skin Meissner’s corpusclesMeissner’s corpuscles – fine touch; light – fine touch; light

pressure; low frequency vibrationpressure; low frequency vibration free nerve endingsfree nerve endings – touch; pressure; pain; – touch; pressure; pain;

temperature changetemperature change


• SubcutaneousSubcutaneous OrganizationOrganization:: Describe the structure of the Describe the structure of the

hypodermis and identify it as a hypodermis and identify it as a general type of membranegeneral type of membrane

• SubcutaneousSubcutaneous Function Function:: Explain the function of the Explain the function of the

hypodermishypodermis

The Subcutaneous The Subcutaneous LayerLayer

• StructureStructure:: loose connective tissueloose connective tissue abundant abundant adipose cellsadipose cells

• FunctionFunction:: stabilizestabilize position of the skin position of the skin energyenergy reserve reserve protectionprotection from mechanical shock from mechanical shock thermal thermal insulationinsulation

Subcutaneous Layer Subcutaneous Layer PropertiesProperties

• elasticelastic• few blood vesselsfew blood vessels• no vital organsno vital organs• good diffusive propertiesgood diffusive properties• excellent for subcutaneous excellent for subcutaneous

injectioninjection

Subcutaneous OrganizationSubcutaneous Organization

Reticular LayerReticular Layer

Subcutaneous Subcutaneous LayerLayer

Loose Connective TissueLoose Connective Tissue

Adipose CellsAdipose Cells

Cutaneous PlexusCutaneous Plexus

Accessory StructuresAccessory Structures

• Hair Follicles & HairHair Follicles & Hair

• Glands in the SkinGlands in the Skin

• NailsNails


• HairHair FolliclesFollicles && HairHair:: Identify the structures of a typical Identify the structures of a typical

hair follicle hair follicle Explain how hair is produced and Explain how hair is produced and

describe mechanisms that determine describe mechanisms that determine hair texture and colorhair texture and color

HairHair

• FactoidsFactoids:: 5 million5 million hairs on the average body; hairs on the average body;

only only 2% on head2% on head Humans have the same number of Humans have the same number of

hair follicles as a gorilla!hair follicles as a gorilla! Not foundNot found on: on: palmspalms, , solessoles, , sides of sides of

fingers & toesfingers & toes, , lipslips, , parts of external parts of external genitaliagenitalia

Hair StructureHair Structure

• Hair RegionsHair Regions:: medullamedulla

core (deep) – core (deep) – from center of matrixfrom center of matrix cells w/ cells w/ softsoft keratinkeratin

cortexcortex superficial – superficial – from edge of matrixfrom edge of matrix cells w/ cells w/ hardhard keratinkeratin

cuticlecuticle most superficial most superficial scale-like dead cellsscale-like dead cells w/ w/ hardhard keratinkeratin

HairHairProductionProduction

• Structural ComponentsStructural Components:: hairhair papillapapilla

connective tissue w/ connective tissue w/ capillariescapillaries & & nervesnerves

nourishes hair-forming cellsnourishes hair-forming cells hairhair bulbbulb – epithelial cells around – epithelial cells around

papillapapilla hairhair matrixmatrix

dividing cellsdividing cells above the bulb above the bulb form hairform hair

papillapapilla bulbbulb

matrixmatrix

Hair TerminologyHair Terminology

• RootRoot from from hair bulbhair bulb to point where internal to point where internal

organization of hair is complete – organization of hair is complete – about ½ way to skin surfaceabout ½ way to skin surface

• ShaftShaft from terminus of from terminus of rootroot to exposed to exposed tip tip

of hairof hair

• Internal Root SheathInternal Root Sheath lower region of folliclelower region of follicle

• External Root SheathExternal Root Sheath from hair matrix to skin surfacefrom hair matrix to skin surface

• Glassy MembraneGlassy Membrane thick basement membrane around the thick basement membrane around the

external root sheathexternal root sheath

NoteNote: layers from deepest to most superficial: layers from deepest to most superficial

Follicle Follicle StructureStructure

Hair Hair RootRoot

Follicle LocationFollicle Location

Follicles extend from the skin Follicles extend from the skin surface to the deep reticular surface to the deep reticular layer or to the upper layer or to the upper subcutaneous layersubcutaneous layer

Hair Growing from FollicleHair Growing from Follicle

Hair FunctionHair Function

• ProtectionProtection

• InsulationInsulation

• SensationSensation

• DisplayDisplay


• ScalpScalp protectionprotection against UV radiation against UV radiation protectionprotection against mechanical shock against mechanical shock insulationinsulation to maintain body to maintain body

temperaturetemperature

• NostrilsNostrils protectionprotection against invasion by insects against invasion by insects

& foreign particles& foreign particles


• EarsEars protectionprotection against invasion by insects against invasion by insects

& foreign particles& foreign particles

• EyelashesEyelashes protectionprotection against UV radiation against UV radiation protectionprotection against invasion by insects against invasion by insects

& foreign particles& foreign particles protectionprotection - channel H - channel H22O away from O away from

eyeseyes


• EyebrowsEyebrows protectionprotection against UV radiation against UV radiation protectionprotection - channel H - channel H22O away from O away from

eyeseyes

• Axillary hair Axillary hair insulationinsulation to maintain body to maintain body

temperaturetemperature protectionprotection against mechanical shock against mechanical shock


• Genital hairGenital hair protectionprotection against UV radiation against UV radiation protectionprotection against invasion by insects against invasion by insects

& foreign particles& foreign particles sensorysensory stimulation stimulation


• General body hairGeneral body hair root hair plexusesroot hair plexuses – tactile – tactile sensationsensation arrector pili musclesarrector pili muscles::

thermal thermal insulationinsulation threat threat displaydisplay

• Other functions of hairOther functions of hair sexual sexual displaydisplay – attraction of mate – attraction of mate genital genital displaydisplay – copulatory aid – copulatory aid

Hair Function & Hair Function & Arrector Pili MusclesArrector Pili Muscles

• Arrector pili muscles:Arrector pili muscles: extend from papillary layer to extend from papillary layer to

connective tissue sheath around connective tissue sheath around folliclefollicle

contraction causes hairs to stand contraction causes hairs to stand erecterect

response to fear – evolved to enlarge response to fear – evolved to enlarge appearance & increase ferocityappearance & increase ferocity

response to cold – evolved to provide response to cold – evolved to provide greater insulationgreater insulation

Types of HairTypes of Hair

• Vellus hairsVellus hairs finefine; “; “peach-fuzzpeach-fuzz”” lightly pigmentedlightly pigmented locuslocus – general body surface – general body surface

• Terminal hairsTerminal hairs heavyheavy; sometimes curly; sometimes curly deeply pigmenteddeeply pigmented lociloci – scalp, eyebrows, eyelashes, – scalp, eyebrows, eyelashes,

axillary hair, genital hairaxillary hair, genital hair

Hair ColorHair Color

• Mature adult colorMature adult color OriginOrigin – melanocytes in follicle matrix – melanocytes in follicle matrix Genetically determinedGenetically determined

• May vary with age due to hormonal May vary with age due to hormonal effectseffects Ex.Ex. The hair of blond children often The hair of blond children often

darkens at pubertydarkens at puberty

Hair Pigment & AgingHair Pigment & Aging

• Hormone effectsHormone effects PubertyPuberty – changes apparent – changes apparent

distribution of distribution of vellusvellus & & terminalterminal hairs hairs by by altering follicle activityaltering follicle activity

• AgingAging Gray – Gray – pigment production pigment production White – White – pigment & air bubbles in pigment & air bubbles in

medulla of shaftmedulla of shaft

Integumentary GlandsIntegumentary Glands

• Sebaceous GlandsSebaceous Glands• Apocrine Sweat GlandsApocrine Sweat Glands• Merocrine Sweat GlandsMerocrine Sweat Glands• Mammary GlandsMammary Glands• Ceruminous GlandsCeruminous Glands


• GlandsGlands ofof thethe SkinSkin:: List and describe the structure of List and describe the structure of

integumentary glandsintegumentary glands Discuss the secretions of Discuss the secretions of

integumentary glands and describe integumentary glands and describe their functionstheir functions

Explain how sweat glands play a Explain how sweat glands play a major role in regulating body major role in regulating body temperaturetemperature

Sebaceous GlandsSebaceous Glands

• StructureStructure:: simple branched alveolarsimple branched alveolar gland gland most attached to most attached to hair follicleshair follicles – general – general

distribution over bodydistribution over body sebaceous folliclessebaceous follicles – oil glands w/out hair: – oil glands w/out hair:

faceface, , backback, , chestchest, , malemale sex organssex organs

• FunctionFunction: : holocrine secretionholocrine secretion oil glands – produce oil glands – produce sebumsebum lubricates skin & hair to retard dehydration; lubricates skin & hair to retard dehydration;

prevent crackingprevent cracking inhibits bacterial growthinhibits bacterial growth

Sebaceous Gland Sebaceous Gland StructureStructure

germinative cellsgerminative cells

hair hair removedremoved

direction of mitosisdirection of mitosis

Holocrine Holocrine SecretionSecretion

Apocrine Sweat GlandsApocrine Sweat Glands

• StructureStructure:: coiled tubular glandcoiled tubular gland attached to attached to hair follicleshair follicles – axillary, – axillary,

mammary, & genital regionsmammary, & genital regions• FunctionFunction: : apocrine secretionapocrine secretion

develop at develop at pubertypuberty produce sticky, cloudy secretionproduce sticky, cloudy secretion odorous after bacterial contactodorous after bacterial contact may have evolved as may have evolved as scentscent for sexual for sexual

attractionattraction

LumenLumen simple simple cuboidal cuboidal

epitheliumepithelium

Apocrine Apocrine SecretionSecretion

Merocrine (a.k.a., Eccrine) Merocrine (a.k.a., Eccrine) Sweat GlandsSweat Glands

• StructureStructure:: coiled tubular glandcoiled tubular gland communicate directly with skin communicate directly with skin

surface via surface via porepore generally distributed over body generally distributed over body

surface (2-5 million)surface (2-5 million) concentratedconcentrated on on palms palms & & solessoles – –

500/cm500/cm22 (300/in (300/in22); also ); also concentratedconcentrated on on headhead

dermal connective dermal connective tissuetissue

lumenlumen

simple simple cuboidal cuboidal

epitheliumepitheliumgland cellsgland cells

Merocrine Merocrine SecretionSecretion

Merocrine (Eccrine) Sweat Merocrine (Eccrine) Sweat GlandsGlands

• FunctionFunction: : merocrine secretionmerocrine secretion produce produce sweatsweat – – 99% H99% H22O w/ 1% NaClO w/ 1% NaCl, ,

& other & other electrolyteselectrolytes, organic , organic molecules, & molecules, & ureaurea

Special functions of sweat:Special functions of sweat:coolingcooling surface of skin – 1 gal/hr surface of skin – 1 gal/hrexcretionexcretion of H of H22O & electrolytesO & electrolytesprotectionprotection from environmental hazards – from environmental hazards –

dilutes harmful chemicals; inhibits dilutes harmful chemicals; inhibits bacteriabacteria

increase gripincrease grip on palms & soles on palms & soles

Apocrine & Merocrine Apocrine & Merocrine Sweat GlandsSweat Glands

Mammary GlandsMammary Glands

• StructureStructure:: compound alveolarcompound alveolar glandgland locuslocus – – breast breast of males (inactive) & of males (inactive) &

females (active)females (active) development and activity depends on development and activity depends on

complex mix of pituitary & complex mix of pituitary & sex sex hormoneshormones

• FunctionFunction: : apocrine secretionapocrine secretion milk glands – produce milk glands – produce mother’s milkmother’s milk nourishes youngnourishes young

Apocrine Apocrine SecretionSecretion

Ceruminous GlandsCeruminous Glands

• StructureStructure:: coiled tubular glandcoiled tubular gland modified sweat glands modified sweat glands locuslocus – – external auditory canalexternal auditory canal

• FunctionFunction: : merocrine secretionmerocrine secretion wax glands – produce wax glands – produce cerumencerumen

in combination w/ sebaceous glands in combination w/ sebaceous glands produceproduce ear waxear wax

traps foreign particlestraps foreign particles

ceruminous ceruminous glandsglands

Gland RegulationGland Regulation

• sebaceoussebaceous & & apocrine sweat glandsapocrine sweat glands:: regulated regulated automaticallyautomatically by autonomic by autonomic

nervous system (ANS) - nervous system (ANS) - involuntaryinvoluntary no regional controlno regional control: all body glands activated : all body glands activated

at same timeat same time

• merocrine sweat glandsmerocrine sweat glands:: regulated by ANS w/ influence from somatic regulated by ANS w/ influence from somatic

nervous system - nervous system - involuntary & voluntary involuntary & voluntary regional controlregional control: palms may sweat while : palms may sweat while

forehead does notforehead does not

NailsNails

• StructureStructure

• FunctionFunction

• LocationLocation


• NailsNails:: Describe the anatomical structure of Describe the anatomical structure of

nails; and, explain how nails are nails; and, explain how nails are formedformed

Discuss differences between the Discuss differences between the epidermis of “exposed” skin and that epidermis of “exposed” skin and that associated with nailsassociated with nails

Nail StructureNail Structure

• LocationLocation:: dorsal surfaces of fingers & toesdorsal surfaces of fingers & toes

• Terms:Terms: nail bednail bed – – under nailunder nail; no str. corneum; no str. corneum nail bodynail body – covers nail bed; – covers nail bed; replaces replaces

str. corneumstr. corneum; tightly compressed ; tightly compressed keratinized cellskeratinized cells

nail rootnail root – – recessed into dermisrecessed into dermis; site of ; site of nail cell productionnail cell production

Nail StructureNail Structure

• Terms: (cont)Terms: (cont) cuticlecuticle ( (eponychiumeponychium) – str. corneum ) – str. corneum

extending over the proximal & lateral sides extending over the proximal & lateral sides of the nail bodyof the nail body

lunulalunula – “little moon” at – “little moon” at proximal edge of proximal edge of nail bodynail body; due to obscured blood vessels; due to obscured blood vessels

hyponychiumhyponychium – thickened str. corneum – thickened str. corneum under leading edge of nail bodyunder leading edge of nail body

free edgefree edge – extends distally – extends distally beyond edge of beyond edge of fingertipfingertip

Nail FunctionNail Function

• Limit distortionLimit distortion of fingertips & toes of fingertips & toes under mechanical stressunder mechanical stress

• Improve manipulationImprove manipulation of small of small objectsobjects

• Something to bite on, scratch with, Something to bite on, scratch with, or pick withor pick with

Local Control ofLocal Control ofIntegumentary FunctionIntegumentary Function

• Injury & RepairInjury & Repair


• InjuryInjury && RepairRepair:: Explain how skin responds to injury Explain how skin responds to injury

and repairs itselfand repairs itself

Repair of InjuriesRepair of Injuries

• Terms:Terms: scabscab – surface blood clot – surface blood clot granulation tissuegranulation tissue – combination of – combination of

blood clot, fibroblasts, & extensive blood clot, fibroblasts, & extensive capillary networkcapillary network

scar tissuescar tissue – acellular, large deposits – acellular, large deposits of collagen fibers, & few blood of collagen fibers, & few blood vessels; relatively inflexiblevessels; relatively inflexible

keloidkeloid – flattened mass of scar tissue – flattened mass of scar tissue growing into surrounding dermisgrowing into surrounding dermis

Major Open WoundsMajor Open Wounds

Injury Repair: Injury Repair: Steps 1 – 4 Steps 1 – 4

Aging And TheAging And TheIntegumentary SystemIntegumentary System

• Aging of the IntegumentAging of the Integument:: Aging affects all components of the Aging affects all components of the

integumentary systemintegumentary system Progressive throughout adult lifeProgressive throughout adult life


• AgingAging:: List ten effects of aging on the List ten effects of aging on the

integument and summarize the integument and summarize the effects of eacheffects of each

Effects Of Aging On The Effects Of Aging On The IntegumentIntegument

1)1) epidermis thinsepidermis thins

2)2) Langerhans cell numbers Langerhans cell numbers decreasedecrease

3)3) vitamin Dvitamin D3 3 synthesis decreasessynthesis decreases

4)4) melanocyte activity declinesmelanocyte activity declines

5)5) glandular activity declinesglandular activity declines

Effects Of Aging On The Effects Of Aging On The IntegumentIntegument

6)6) dermal blood supply is reduceddermal blood supply is reduced7)7) hair follicles stop functioning or hair follicles stop functioning or

produce finer, thinner hairsproduce finer, thinner hairs8)8) dermis thins as elastin fibers dermis thins as elastin fibers

decreasedecrease9)9) reduction in sex hormones causes reduction in sex hormones causes

changes in hair & body fat changes in hair & body fat distributiondistribution

10)10) skin repair process slowsskin repair process slows

Skin SignsSkin Signs

Review of Integumentary Review of Integumentary StructureStructure

11

Documents

Integumentary System