Download - Four Types of Tissues - BioRocks-2ttbiorocks-2.weebly.com/.../4/...types_of_tissues__epithelial_tissues.pdf · Four Types of Tissues • Four Types of Tissue (cont’d) – Connecve

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FourTypesofTissues•  Tissuesarecollec8onsofcellsandcellproductsthatperformspecific,limited

func8ons

•  FourTypesof8ssue– Epithelial*ssue

•  Coversexposedsurfaces•  Linesinternalpassageways•  Formsglands


FourTypesofTissues•  FourTypesofTissue(cont’d)

–  Connec*ve*ssue•  Fillsinternalspaces•  Supportsother8ssues•  Transportsmaterials

•  Storesenergy

– Muscle*ssue•  Specializedforcontrac8on•  Skeletalmuscle,cardiacmuscle,&smoothmuscle

–  Neural*ssue•  Carrieselectricalsignalsfromonepartofthebodytoanother


EpithelialTissues

•  Epithelia– Layersofcellscoveringinternalorexternalsurfaces

•  Glands– Structuresthatproducesecre8ons


EpithelialTissues

•  Characteris*csofEpithelia– Cellularity(celljunc8ons)

– Polarity(apicalandbasalsurfaces)

– AQachment(basallamina)

– Avascularity

– Regenera8on


EpithelialTissues

Figure4–1ThePolarityofEpithelialCells.


EpithelialTissues

•  Func*onsofEpithelialTissue– Providephysicalprotec8on

– Controlpermeability

– Providesensa8on

– Producespecializedsecre8ons(glandularepithelium)


EpithelialTissues

•  MaintainingtheIntegrityofEpithelia

–  Intercellularconnec8ons

– AQachmenttobasallamina

– Epithelialmaintenanceandrepair


EpithelialTissues

•  IntercellularConnec8ons–  Celljunc8ons

•  Formbondswithothercellsorextracellularmaterial:

–  Tightjunc*ons

–  Gapjunc*ons

EpithelialTissues

•  CellJunc8ons– Tightjunc8ons—betweentwoplasmamembranes

•  Preventspassageofwaterandsolutes•  Isolateswastesinthelumen

– Gapjunc8ons—allowrapidcommunica8on•  Heldtogetherbychannelproteins•  Allowionstopass



EpithelialTissues•  CellJunc8ons– Desmosomes

• Actasintercellularcement

•  Spotdesmosomes– 8ecellstogether– allowbendingandtwis8ng


EpithelialTissues

•  EpithelialMaintenanceandRepair

– Epitheliaarereplacedbydivisionofstemcells

– Nearbasallamina


Classifica8onofEpithelia•  Singularepithelium;pluralepithelia

•  ClassesofEpithelia–  Basedonshape

•  Squamousepithelia:thinandflat

•  Cuboidalepithelia:squareshaped•  Columnarepithelia:tall,slenderrectangles

–  Basedonlayers•  Simpleepithelium:singlelayerofcells

•  Stra8fiedepithelium:severallayersofcells


Classifica8onofEpithelia



Figure4–3SquamousEpithelia.



Figure4–4CuboidalEpithelia.



Figure4–5ColumnarEpithelia.