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Download 5 Anat 35 Histology
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HumanAnatomy Unit1 HISTOLOGY InAnatomyToday Histology • Studyoftissues • Tissues=agroupofcells performingacommon function • Microscopicanatomy • Includeshowdifferenttissues arearrangedtoformorgans andotherstructures Ductusepididymis TissueSections Longitudinalsections Transverseorcross section TissueSections 4TissueTypes • 4Typesoftissue – Epithelialtissue – Connectivetissue – Nervoustissue – Muscletissue • CharacteristicDifferences – Proportionofcellstomatrix – Matrixcomposition – Cellfunction EpithelialTissue • Composition – Oneormorelayersofcloselyadheringcells – Apicalsurfaceandbasalsurface – Restonabasementmembrane – Supportedbyconnectivetissues • Function – Coverorgansurfaces – Formsecretorytissue – Formductsofglands Classification • Criteria – Numberofcelllayers – Morphologyofthesurface cells • Twomajorcategories – Simple(onelayer) – Stratified(twoormore layers) CellShape • Squamous • Columnar • Cuboidal • Acinar SimpleEpithelia • General – Allcellstouchbasementmembrane • Exception:Pseudostratifiedcolumnar • Categories – Simplesquamous – Simplecuboidal – Simplecolumnar – Pseudostratifiedcolumnar SimpleEpithelia SimpleSquamousEpithelium SimpleCuboidalEpithelium SimpleColumnarEpithelium • Foundin – – – – Stomach Smallintestines Colon Appendix • Singlelayerofcells • Nucleiuniformly arranged GobletCellEpithelium • Simplecolumnar epitheliumwith numerousgobletcells present • Gobletcellsproduce mucus • Foundin: – Smallintestine – Colon PCCE • Pseudostratifiedciliated columnarepithelium • Singlelayerofcells • Ciliapresentonthe apicalsurface Cilia Ciliaarecomposedofmicrotubulesand projectfromtheapicalsurface. Function:tomovethingsacrossthecell surface StratifiedEpithelia • Generalcharacteristics – Upto20ormorecelllayers – Namedforshapeofsurfacecells • Exception:transitionalepithelium • Stratifiedsquamous – – – – Mostcommon Exfoliation Keratinizedtissue(cornified) Nonkeratinized StratifiedSquamousEpithelium • Multiplelayersof cells • Surfacelayercells aresquamous • Foundinareasthat experiencefriction – Epidermis – Vagina StratifiedCuboidalEpithelium • Multiplelayersof cuboidcells • Surfacelayerofcellsare cuboidal • Foundin – Largeductsofglands • Sweatglands • Pancreas TransitionalEpithelium • Foundinsecretory portionsoftheurinary system – Calyces – Ureters – Urinarybladder • Distensibletissue (stretches) • Epithelium“transitions” fromcuboidaltoalmost squamousinappearance astissuedistends ConnectiveTissue • Lesscells,moreECF(groundsubstance) • Variable,widelydistributed,mostabundant • Threecategoriesofmaturetissue – FibrousCT – SupportiveCT(bone,cartilage) – FluidCT(blood) ConnectiveTissueFunctions • Bindsorgans • Support • Protection – Physical – Immune • • • • Movement Storage Heatproduction Transportation FibrousConnectiveTissue:Components • Cells – Fibroblasts – Macrophage – Leukocytes – PlasmaCells – MastCells – Adipocytes • Fibers – Collagenous – Reticular – Elastic – Groundsubstance TypesofFibrousConnectiveTissue • LooseCT – Lotsofground substance – Types • Areolar • Reticular • Adipose • DenseCT – Fiberispredominant component – Types • Denseregular • Denseregularelastic • Denseirregular AreolarConnectiveTissue • Cells – Allsixtypes • Matrix – Predominatelycollagenous – Someelastic/reticular • General – – – – Veryvascular Looselyorganized Varied Underliesalmostallepithelial tissue • Theseimagesareof mesentery ReticularConnectiveTissue • Reticularfibersand fibroblasts • Providessupporting framework(stroma), networkorlattice • Found – – – – Spleen Lymphnodes Thymus Bonemarrow AdiposeTissue • Adipocytesmostabundantcell type • SupportedbyareolarCT, reticularCT,bloodvessels • Function: – – – – Energystorage Insulates Supports Cushionsshock • Whitefatvs.Brownfat DenseRegularConnectiveTissue • “regular” arrangement offibroblastand collagenfibers – Closelypackedparallel collagenfibers+ fibroblasts – Formbundlesof collagenfibers • Foundintendons DenseRegularElasticConnective Tissue • Largeamountofelastic fibersinparallel arrangement • Elasticfiberscanstretch1 ½timestheirlengthand thenrecoil • Provideselasticity • Found – Ligaments – Largearteries – Bronchialtubes DenseIrregularConnectiveTissue • Collagenfibersin randomarrangement+ fibroblasts • Found – Reticularlayerofdermis – Protectivecapsule aroundorgans – Fibroussheetaround bones,etc. • Similartoareolar,but less“open” space Cartilage • Flexiblematrix • Avascularexceptwhen transformingtobone • Externalear,tipofnose, larynx • Cells – Chondroblasts • Threetypes – Hyaline – Elastic – Fibrocartilage • secretematrix – Chondrocytes • trappedinlacunae HyalineCartilage • Matrix – smooth,frictionless – mixofcollagen,elastin, chondroitin(aglucosaminoglycan) • Cells – Cellnests • Usuallycoveredby perichondrium – DenseirregularCTcovering – innerlayerproducesnew chondrocytes • Examples: – Costalcartilage – Nasalseptum – C-ringcartilageof trachea – Fetalskeleton ElasticCartilage • Matrix – Web-likemeshofelastic fibers – Appearanceoffur • Perichondriumalways present • Examples: – Pinnaofear – Epiglottis Fibrocartilage • Characteristics – Parallelcollagenfibers – Rowsofchondrocytes inlacunae – Noperichondrium • Examples – Pubicsymphysis – Intervertebraldiscs – Menisciofthesynovial joints SupportiveConnectiveTissue:Bone CompactBone • Novisiblespaces • Densecalcifiedtissue • Found – Externalsurfaceofallbone – Shaftsoflongbones • Tissuearrangedinto osteons – Concentriclayersofmatrix andosteocytes surroundingacentralcanal • Periosteum SpongyBone • Found – Headsoflongbones – Middlelayerofroofing bonesofskull • Namedforappearance • Tissuearrangedinto trabeculae(fusionof spicules) • Bathedinredmarrow FluidConnectiveTissue:Blood • Plasma+formed elements • Erythrocytes • Leukocytes – – – – – Neutrophils Basophils Eosinophils Monocytes Lymphocytes • Thrombocytes NervousTissue • Excitabletissue • Function – Rapidcommunication • Celltypes – Neurons – Neuroglia MuscularTissue • Contractswhenstimulated • Threetypes – Skeletal – Cardiac – Smooth
