The integument - Lazarov

The integumentThe integument1.1. Skin and its main functions Skin and its main functions 2.2. Structure of the skin:Structure of the skin:

�� epidermis epidermis –– microscopic structuremicroscopic structure�� dermis dermis –– microscopic structuremicroscopic structure�� hypodermis (subcutaneous tissue)hypodermis (subcutaneous tissue)

3.3. Appendages of the skin:Appendages of the skin:�� hairs and nailshairs and nails�� sebaceous and sweat glandssebaceous and sweat glands

4.4. Mammary gland, mammaMammary gland, mamma

Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 2

Skin and skin functionsSkin and skin functions� the largest single organ of the body: ~16% (~4 kg) of the total body weight

�� majormajor rolerole –– a barrier between the organism and the environment:a barrier between the organism and the environment:

�� pprotectrotectionion of the body against pathogens and damage

� some other functionsother functions:� thermal insulation and heatheat regulationregulation

�� eexcretionxcretion by sweating � temperature regulation

�� ccontrol of evaporationontrol of evaporation and water resistanceand water resistance:�� prevents prevents excessive water loss and body dessication

�� sstorage and synthesistorage and synthesis::� storage center for lipids and water

� synthesis of vitamin D

�� absorptionabsorption –– oxygen, nitrogen and carbon dioxide, medicine

�� ssensationensation – nerve endings, cutaneous receptors

�� aaesthetics and communicationesthetics and communication

Human skinHuman skin

NB: NB: The adjective The adjective cutaneouscutaneous literally means literally means

““of the skin" (from Latin cutis, of the skin" (from Latin cutis, skinskin))

Prof. Dr. Nikolai LazarovProf. Dr. Nikolai Lazarov 3NB: NB: HumanHumanHumanHumanHumanHumanHumanHuman skin:skin:skin:skin:skin:skin:skin:skin: the most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 mthe most valuable 2 m22222222!!!!!!!!


Structure of the skinStructure of the skin� two major layers major layers –– Gr. Gr. dermaderma, skin:, skin:

�� epidermisepidermis�� epithelial layerepithelial layer� derived from embryonic ectodermectoderm� generates skin appendagesskin appendages�� high capacity of regenerationhigh capacity of regeneration�� nonnon--vascular vascular but richly innervatedinnervated

�� dermisdermis (corium)�� connective tissue layerconnective tissue layer�� mesenchymal originmesenchymal origin�� highly vascularized highly vascularized

�� hypodermishypodermis (subcutis)� loose irregular connective and fatty tissue, irregular connective and fatty tissue,

panniculus adiposuspanniculus adiposus

�� two skin typestwo skin types –– thickness of the epidermisthickness of the epidermis::�� thick (glabrous, hairless) skinthick (glabrous, hairless) skin

�� palms and soles palms and soles –– 1.5 mm1.5 mm�� thin (hairy) skin thin (hairy) skin –– 0.08 m0.08 mmm

�� elsewhere on the bodyelsewhere on the body�� thinnest on the eyelidsthinnest on the eyelids – 0.05 mm



DactyloscopyDactyloscopy�� skin surface:skin surface:

�� "epidermal ridges"epidermal ridges““,

cristae cutiscristae cutis

�� sulci cutissulci cutis

�� fingerprintfingerprint = = impression of the friction ridges on all parts of the finger

�� dactyloscopydactyloscopy = = fingerprint identification, palm print identification



DermatoglyphicsDermatoglyphics� dermatoglyphs are present on fingers, palms, toes, and soles� dermatoglyphic patterns give insight into a critical period of embryogenesis and

often relate to chromosomal abnormalities and genetic disorders

Gr. Gr. ddermaerma,, skin, skin, glyphglyph, , carvingcarving –– the scientific study of the scientific study of fingerprintsfingerprints

whorl patternwhorl patternwhorl patternwhorl patternwhorl patternwhorl patternwhorl patternwhorl pattern loop patternloop patternloop patternloop patternloop patternloop patternloop patternloop pattern



EpidermisEpidermis�� stratified squamous keratinized epitheliumstratified squamous keratinized epithelium�� main cell types:main cell types:

�� keratinocyteskeratinocytes –– 8585--95% of all epidermal cells95% of all epidermal cells�� keratinkeratin--producing cellsproducing cells

�� melanocytesmelanocytes�� neural crest cellsneural crest cells�� production and storage of melaninproduction and storage of melanin�� darkening of the skin (tanning)darkening of the skin (tanning)

�� Langerhans cellsLangerhans cells –– 22--8%8%�� bonebone--marrowmarrow--derived macrophagesderived macrophages� dendritic cells with Birbeck granules�� immune, immune, antigenantigen--presenting cellspresenting cells

�� Merkel cellsMerkel cells� present in the thick skinin the thick skin� "touch cells" � mechanoreceptorsmechanoreceptors�� APUD cellsAPUD cells �� neuroendocrine functionneuroendocrine function



Epidermis Epidermis –– microscopic structuremicroscopic structure�� 5 layers of keratinocytes:5 layers of keratinocytes:

�� stratum basale (germinativum)stratum basale (germinativum)�� single layer of columnar cellssingle layer of columnar cells�� renewal of the epidermisrenewal of the epidermis

�� stratum spinosum stratum spinosum �� several layers of polygonal spiny cellsseveral layers of polygonal spiny cells

�� desmosomesdesmosomes�� stratum granulosumstratum granulosum

�� 33--5 layers of flattened polygonal cells 5 layers of flattened polygonal cells with keratohyalin granuleswith keratohyalin granules

�� stratum lucidumstratum lucidum�� only in thick skinonly in thick skin�� flattened eosinophilic cellsflattened eosinophilic cells

�� stratum corneumstratum corneum�� 1515--20 layers of flattened nonnucleated 20 layers of flattened nonnucleated

keratinized (horny) cells keratinized (horny) cells

�� keratinization:keratinization:�� every 15every 15--30 days30 days�� due to mitotic activity of the malpighian layerdue to mitotic activity of the malpighian layer


NB: NB: Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics Mnemonics for remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skinfor remembering the layers of the skin::::

"Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep) "Cher Likes Getting Skin Botoxed" (from superficial to deep)

"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)"Before Signing, Get Legal Counsel" (from deep to superficial)


Dermis, coriumDermis, corium�� connective tissueconnective tissue –– though, flexible and elasticthough, flexible and elastic

�� variable thicknessvariable thickness –– max. 4 mm on the backmax. 4 mm on the back

�� two layers:two layers:�� papillary layerpapillary layer –– thin andthin and superficial:superficial:

�� dermal papillaedermal papillae � ridges�� loose connective tissueloose connective tissue

•• collagen fiberscollagen fibers �� anchoring fibrilsanchoring fibrils•• fibroblasts, mast cells, macrophagesfibroblasts, mast cells, macrophages

�� increase and reinforceincrease and reinforce dermaldermal--epidermal junctionepidermal junction

�� reticular layerreticular layer –– deep and much thicker:deep and much thicker:� irregular dense connective tissue

•• collagen type I and elastic fiberscollagen type I and elastic fibers•• fewer cellsfewer cells

� rich lymph and capillary networkcapillary network– 4.5% of the blood volume

�� epidermal derivativesepidermal derivatives



Dermis Dermis –– microscopic structuremicroscopic structureHuman skinHuman skin


HypodermisHypodermis�� subcutaneous tissue subcutaneous tissue –– synonyms: synonyms:

superficial fascia, superficial fascia, panniculus adiposus:panniculus adiposus:� loose connective tissue and elastin

� binds the skin loosely to the subjacent organs� supplying skin with blood vessels and nerves � renewal of the epidermis

�� components:components:�� fat cells fat cells – varying in number and size,

contains 50% of body fat�� fibroblasts, macrophagesfibroblasts, macrophages



Skin appendagesSkin appendages� appendages associated with the skin:skin:

�� hairshairs – functions:�� ssensationensation�� heat lossheat loss�� filter for breathingfilter for breathing�� protectionprotection

�� nails nails – function:�� protectionprotection

�� sebaceous glands sebaceous glands – function:�� secrete sebum onto hair follicle secrete sebum onto hair follicle

to oil the hairto oil the hair

�� sweat glands sweat glands – function:�� produce sweat to help keep the body coolproduce sweat to help keep the body cool�� secreted with strong odour (apocrine)secreted with strong odour (apocrine), ,

with a faint odour (eccrine)with a faint odour (eccrine)

�� arrector pilli muscle arrector pilli muscle – function:�� smooth muscle that pullsmooth muscle that pullss hairs straighthairs straight



Hairs and their embryogenesisHairs and their embryogenesis�� Lat. Lat. pillipilli, Gr. , Gr. thryx, thrychosthryx, thrychos� elongated keratinized structures::

�� found everywhere with exception offound everywhere with exception of:� palms and soles� lips and eyelids � glans penis� glans clitoridis and labia minora

�� arise from an epidermal invagination, arise from an epidermal invagination, hair folliclehair follicle

�� embryonic development:embryonic development:�� epidermal proliferationsepidermal proliferations

penetrating the underlying dermis�� hair papillaehair papillae, invaginations filled

with mesoderm� vessels and nerve

endings develop�� dermal root sheathdermal root sheath –

formed by surrounding mesenchyme


curly and straight hairscurly and straight hairs


Hair structure and colourHair structure and colour�� three partsthree parts length-wise::

�� hair bulbhair bulb – stem cells�� hair roothair root – beneath the skin surface�� hair shafthair shaft – above the skin surface

�� three parts in crossthree parts in cross--section:section:�� hair medullahair medulla – area in the core:

�� contains loose cells contains loose cells and airspacesand airspaces

�� hair cortexhair cortex :�� contains densely packedcontains densely packed keratinkeratin� responsible for the pigmentation,

shape and texture of hair � hair cuticle :

� single layer of cells covering the cortex

� last cell line to differentiate

� natural hair colourshair colours:� phaeomelanin – responsible for

the yellowishyellowish--blond to redblond to red colors� eumelanin is responsible for

the brown to blackbrown to black shades�� ggray hairray hair – little or no pigment



Hair follicle structureHair follicle structure�� papilla:papilla:

�� connective tissueconnective tissue and a capillary loopand a capillary loop�� hair matrix:hair matrix:

�� epithelial epithelial cellscells and melanocytesmelanocytes�� rroot sheathoot sheath –– two coats:two coats:

�� external external (outer) (outer) root sheathroot sheath�� internal internal (inner) (inner) root sheathroot sheath – three layers::

�� stratum epitheliale pallidum stratum epitheliale pallidum ((HenleHenle’’s s layerlayer))�� stratumstratum epithelialeepitheliale granuliferumgranuliferum ((HuxleyHuxley’’ss layerlayer))� internal cuticle

� glassy membrane – noncellular hyaline layer



Sebaceous glandsSebaceous glands� small, sacculated, holocrine glands:

� embedded in the dermis; 100 glands/cm2

� absent in the glabrous skin of palms and soles� 400-900/cm2 on the face, forehead and scalp� begin to function at puberty

�� structure:structure:�� secretory portion:secretory portion:

�� 22--5 acini 5 acini of undifferentiated flattened epithelial cells� larger fatfat--containing sebaceous cellscontaining sebaceous cells�� basal laminabasal lamina

�� single short duct:single short duct:�� in the upper portion of a hair folliclein the upper portion of a hair follicle

�� sebum sebum (Lat, (Lat, fatfat or or tallowtallow) ) – functions:�� complex mixture of lipids and waxes, complex mixture of lipids and waxes,

triglycerides, squalene and cholesteroltriglycerides, squalene and cholesterol�� natural lubricant ofnatural lubricant of the hairthe hair and skinand skin�� antibacterial and antifungal propertiesantibacterial and antifungal properties�� no importance in preventing water lossno importance in preventing water loss



Sudoriferous (sweat) glandsSudoriferous (sweat) glandsHuman skinHuman skin

� widely distributed in the skin� absent in the glans penis

�� two types:two types:�� eccrine (merocrine) glands:eccrine (merocrine) glands:

� most numerous� simple, coiled tubular glands�� ducts opened at the skin surfaceducts opened at the skin surface� secretory portion in the dermis,

surrounded by myoepithelial cells•• dark (mucoid) cellsdark (mucoid) cells � glycoproteins•• clear cellsclear cells – no secretory granules

� innervated by cholinergic nerve endingscholinergic nerve endings�� apocrine glands:apocrine glands:

�� in in axillaeaxillae,, eyelids, eyelids, areola areola andand nipple, nipple, anal regionanal region, , embedded in the subcutaneous tissueembedded in the subcutaneous tissue

�� much larger (3much larger (3--5 mm in diameter)5 mm in diameter)� tubular with extensive coiled secretory portioncoiled secretory portion� cuboidal cells with secretory granules� straight ducts opened into hair folliclesducts opened into hair follicles� produce odorless viscous secretionodorless viscous secretion� innervated by adrenergic nerve endingsadrenergic nerve endings

�� sweat sweat – functions:�� clearclear andand notnot viscous,viscous, saltysalty fluidfluid � keepkeep thethe bodybody coolcool� proteins, water, sodium chloride, urea, uric acid


NailsNails�� Lat. Lat. unguesungues, Gr. , Gr. onyx, onychosonyx, onychos� fingernails and toenails –

on the dorsal surface of each distal phalanx::�� tough tough keratinkeratin

as animals' hooves and hornshooves and horns�� nail parts:nail parts:

�� rootroot –– proximal partproximal part�� bodybody –– exposed partexposed part�� free borderfree border –– distal enddistal end

�� structure:structure:�� matrixmatrix – the only living part of the nail�� eponychium (cuticle)eponychium (cuticle)�� paronychiumparonychium – the 'live' skin�� hyponychiumhyponychium�� nail platenail plate – layers of keratin�� nail badnail bad – pink colour of the nail�� lunulalunula – visible whitish crescent part of the matrix

�� nail foldnail fold – overlaps the base and sides of nails

�� nail groovenail groove – guide the direction of nail growth


Femal mamma, breastFemal mamma, breast

1.1. Embryonic developmentEmbryonic development2.2. Functional morphologyFunctional morphology3.3. Blood supplyBlood supply4.4. Lymphatic drainageLymphatic drainage5.5. InnervationInnervation


BreastBreast

Embryonic developmentEmbryonic development�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,

growth of a basic milk streakmilk streak

� formation of mmilk lines, ilk lines, "ventral epidermal ridges""ventral epidermal ridges" –sixth week of the embryo's "life"sixth week of the embryo's "life"

�� embryonic originembryonic origin::� ectodermal – parenchyma

� mammary papilla (nipple), alveoli, lactiferous ducts

� mesenchymal – stroma� adipose tissue

� persist of mammary ridges� polymastia (accessory breastsalong the milk line from axillae to groin)

polythelia (supernumerary nipple)


BreastBreast

Embryonic developmentEmbryonic development�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,









BreastBreast

Embryonic developmentEmbryonic development

Artemis of EphesusArtemis of Ephesus

with tier upon tier of breasts to highlight with tier upon tier of breasts to highlight her ability to nurtureher ability to nurture

�� modified sudoriferous glandsmodified sudoriferous glands�� beginbegin – fourth week of gestationfourth week of gestation,









Topographic anatomyTopographic anatomyBreastBreast


Adult breast anatomyAdult breast anatomy

� parenchyma mammaeparenchyma mammae – glandular tissue of the tubuloalveolar type� 15-20 lobes, lobi glandulae mammariae:

� cluster of rounded alveoli – alveolar and myoepithelial cells� ducts and ductules – ductus lactiferus, sinus lactiferus, porus lactiferus

� stroma mammaestroma mammae – fibrous and adipose (fatty) tissue� suspensory ligaments (of Cooper)

� areola mammae:areola mammae:� areolar glands (of Montgomery)� papilla mammaria (nipple)

BreastBreast

NB: NB: The ratio of glands to adipose tissues rises from 1:1 The ratio of glands to adipose tissues rises from 1:1

in nonlactating women to 2:1 in lactating womenin nonlactating women to 2:1 in lactating women!


Microscopic structureMicroscopic structure

�� functional stagesfunctional stages::� childish breast (before puberty)� juvenile breast� adult resting mammary gland� mammary gland during pregnancy� lactating mammary gland

BreastBreast


� superficialsuperficial plexus � nodi lymphoidei axillares (75% of the lymph)� deepdeep (fascial) plexus � nodi lymphoidei mediastinales

� lymphatic pathway of GrossmanGrossman � nodi lymphoidei apicales (infraclaviculares)� lymphatic pathway of GerotaGerota � nodi lymphoidei hepatici et subdiaphragmatici

BreastBreast

Blood vessels and lymphatic drainageBlood vessels and lymphatic drainage


BreastBreast

Lymphatic drainagLymphatic drainag ee


Axillary lymph nodesAxillary lymph nodes�� 5 5 groupsgroups (20-40 nodes):

�� apical groupapical group – 6-12 nodes, nodi lymphatici apicalesnodi lymphatici apicales(infraclavicularesinfraclaviculares)

�� central groupcentral group – 4-6 nodes, nodi lymphatici centralesnodi lymphatici centrales

�� anterior (pectoral) groupanterior (pectoral) group – 4-5 nodes,nodi lymphatici mediales (pectorales)

�� posterior (subscapular) groupposterior (subscapular) group –6-7 nodes,

nodi lymphatici subscapularesnodi lymphatici subscapulares

�� lateral grouplateral group – 3-8 nodes, nodi lymphatici lateralesnodi lymphatici laterales

BreastBreast


Clinical significanceClinical significanceBreastBreast

GynecomastiaGr. γυνή gyne, "woman" and µαστός mastos, "breast"

Breast cancerPaget's disease Paget's disease (morbus Paget)(morbus Paget) – a special type of ductal carcinoma

Mammography


� sympathetic fiberssympathetic fibers � along the blood vessels� sensory fiberssensory fibers � rami glandulares of rami perforantes of the intercostal nerves

� rr. mammarii mediales � rr. cutanei anteriores II-VI intercostal nerve� rr. mammarii laterales � rr. cutanei lateralis IV-VI intercostal nerve

BreastBreast

Breast innervationBreast innervation


BreastBreast

Thank youThank you……

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The integument - Lazarov