2. Epithelial Tissue14.Lect

EPITHELIAL TISSUE

EPITHELIAL TISSUEClass PrayerFather of Light and Wisdom,thank you for giving usa mind that can knowand a heart that can love.Let us remember that we are in the holy presence of GOD.In the name of the Father and of the Son and of the Holy Spirit. Amen.Help us to keep learning every day of our life--no matter what the subject may be.Let us be convinced that all knowledge leads to youand let us know how to find you and love youin all the things you have made.Class PrayerClass PrayerEncourage us when the studies are difficultand when we are tempted to give upEnlighten us when our brain is slowand help us to grasp the truth held out to us.Amen.Saint John Baptist de la Salle, Pray for us.Live Jesus in our hearts, Forever.Organization of the Human BodyBASIC TISSUES cell basic morphologic and functional unit of all living thingstissue combination of cells with same general functionorgancombination of tissues that form a more complex functional unit organ systemorgans that have interrelated functions.

BASICepithelial tissueBASIC TISSUES epithelial tissue (epithelium)connective tissuemuscle tissue nervous tissue each basic tissue actually consists of a group of tissues that have common morphological characteristics. epithelial tissueepithelial tissue: characteristicshighly cellular avascularcells exhibit polarity surfaces identifiable by position of organelles and surface modifications basallateral superficial (apical).

http://www.life.uiuc.edu/csb/213/PDF/11.pdfepithelial tissue: originectoderm e.g. epidermis and appendages of skin; and corneamesoderm e.g., heart, blood and lymphatic vessels, serous cavities, urinary system (except for urinary bladder and urethra), male and female reproductive systemsendoderme.g., GIT except mouth and anus (ectoderm), liver, gall bladder, pancreas, respiratory tract, urinary bladder and urethra.Epithelium surface epitheliumcovering epithelium-covers external body surfaceslining epithelium - lines body cavities and ducts of glands with ducts glandular epitheliumforms glands cells are specialized to produce macromolecules (secretions).: General ClassificationBasal Lamina layer of amorphous extracellular materialwhere basal surfaces of epithelial cells restseparates epithelial cells from underlying connective tissuealso envelops muscle, fat and Schwann cells, and cells of adrenal medullain epithelium, produced by epithelial cells

http://www.dls.ym.edu.tw/lesson/five.files/121.GIFBasal Lamina20-100 nm thickseen only usingEMspecial histochemical techniquelayerslamina rara externa (lamina lucida) electron-lucent area related to epithelial cellsglycoproteins including lamininlamina densaelectron densenetwork of fine filaments consisting of type IV collagenlamina rara internaelectron-lucent; similar to 1not always present.

http://www.life.uiuc.edu/csb/213/PDF/11.pdfbasal lamina lamina fibroreticularisin some epitheliaextracellular material with reticular fibers and fibronectin that underlies basal lamina produced by fibroblaststhicker than basal lamina (200-500 nm)visible under routine histo preparations some authors use term synonymously with basal lamina.

Trachea, x40Basement Membrane

surface epithelium covering epitheliumlining epithelium glandular epitheliumforms secretory portion of all glands (note: categories overlap; certain cells of many lining epithelia are secretory.) surface epitheliumEpithelium surface epithelium: General Classificationaccording to number of cell layers: classificationsimple epitheliumsingle layer of cellsstratified epitheliummore than one layer of cells

http://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumaccording to presence of cell modificationsexample,ciliated epitheliumcells with cilia

http://www.pathguy.com/histo/086.htmsimple epithelium:: classificationsimple epitheliumsingle layer of cellsstratifiedmore than one layer of cells

http://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumaccording to number of cell layerssimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

simple squamoussimple squamoussingle layer of flattened cellsirregularly polygonal when seen from surfacee.g.lining inactive thyroid folliclelining peritoneum.

http://www.life.uiuc.edu/csb/213/PDF/11.pdf

surface epithelium: classificationsome have special names:

http://www.mefst.hr/vms/atlas/hist/img_hista/big/K_5.jpgsimple squamous

http://erl.pathology.iupui.edu/HISTO/WEBJPGS/EPI_04W.JPGendotheliumlines luminal surface of heart and blood vesselsmesothelium lines serous surfaces pericardium envelops heartperitoneum envelops or lines many abdominal organspleura envelops lungs.surface epithelium: classificationsimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

simple squamoussimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

simple cuboidalsimple cuboidalsingle layer of cuboidal cellse.g.some ducts of salivary glands and pancreascollecting tubules of kidney surface of ovary .

Parotid, x400

surface epithelium: classificationsimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

simple cuboidalsimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

simple columnarsimple columnarsingle layer of tall cellsnuclei occupy same planebasally locatede.g., stomach and intestines large ducts of exocrine glands ciliated type lines uterus and oviductsgallbladder, etc.. Gallbladder, x40 (ciliated)



simple columnarsimple epithelium:: classificationhttp://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumsquamous cells flattenedcuboidalcells equally tall as widecolumnarcells taller than they are widepseudostratifiedcells appear to be more than one layer

pseudostratified columnarpseudostratified columnarsingle layer of cellsnuclei occupy different levelslines membranous and spongy parts of the male urethra ciliated type referred to as respiratory epithelium.Trachea, x 400



pseudostratified columnarsimple epithelium:according to number of cell layers:: classificationsimple epitheliumsingle layer of cellsstratified epitheliummore than one layer of cells

http://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumaccording to number of cell layers:: classificationsimple epitheliumsingle layer of cellsstratified epitheliummore than one layer of cells

http://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epitheliumstratified epithelium: classificationsurface epitheliumclassified according to shape of cells on most superficial layerstratified epitheliumstratified squamous: classificationsurface epitheliumsquamouscuboidalcolumnartransitionalstratified epitheliumstratified squamousseveral layers of cellssuperficial layer flatdeep layers tall cuboidal or columnar

http://www.life.uiuc.edu/csb/213/PDF/11.pdfsurface epithelium: classificationstratified squamous: typeskeratinizedepithelium is drysuperficial cells lose nuclei and filled with keratine.g., skinnonkeratinized epithelium is wetsuperficial cells still with nucleuse.g. esophagus, vagina, cornea (note: a misnomer because cells also contain keratin).

Thick skin, x100Cervix, x100

surface epithelium: classification: classificationsurface epitheliumsquamouscuboidalcolumnartransitionalstratified epitheliumstratified cuboidalstratified cuboidalusually two or three layers of cuboidal cellse.g., larger ducts of major salivary glands.

surface epithelium: classificationstratified columnar: classificationsurface epitheliumsquamouscuboidalcolumnartransitionalstratified epitheliumSalivary glandhttp://cellbio.utmb.edu/microanatomy/epithelia/stratified_columnar.htmstratified columnarraree.g., lining of large ducts of some exocrine glands in some areas of body, as in parts of larynx, is ciliated.

surface epithelium: classificationstratified epithelium: classificationsurface epitheliumsquamouscuboidalcolumnartransitionaltransitionaltransitionalurinary passages and bladder designed to withstand stretching

surface epithelium: classificationtransitionalhttp://www.meddean.luc.edu/lumen/MedEd/Histo/HistoImages/hl7A-44.jpgin distended state:transforms into a thin stratified squamous epithelium. in contracted state of organ:essentially stratified cuboidal superficial cells (referred to as umbrella cells) bulge out into lumen giving cells a dome-shaped profile

urinary bladder

surface epithelium: classificationcovering epithelium: surface modification of cells needed for functionpresent in apical surface lateral surface basal surface apical surface lateral surface basal surfacesurface epitheliumcovering epithelium: surface modification of cells apical surface lateral surface basal surfacemicrovilli cilia (Kinocilia)flagellastereocilia.

fine, finger-like processes in most epithelial cells1 mm long; 0.08 mm diameterfew to thousands per cellbrush border or striated border (LM)Small intestine, x 400on their surfaces are glycolipid and glycoprotein molecules (i.e., glycocalyx)core consists of actin filamentsincrease cell surface area.

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htm

surface epitheliumfingerlike extensions of plasma membrane motile - beat sequentially or synchronously in just one directionlonger (7-10 mm) and thicker (0.2 mm) than microvilli. EM structure of axoneme (core)central pair of microtubulesnine doublets surrounding central pairaxoneme attached to basal body or centriolecovering epithelium: surface modification of cells apical surface lateral surface basal surfacemicrovilli cilia (Kinocilia)flagellastereocilia.

Trachea, x400

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htm

surface epitheliumsame structure, but are much longer, than ciliain humans, present in only one cell type, spermatozoon (tail).

covering epithelium: surface modification of cells apical surface lateral surface basal surfacemicrovilli cilia (Kinocilia)flagellastereocilia.

surface epithelium apical surface

microvilli cilia (Kinocilia)flagellastereocilia.

covering epithelium: surface modification of cells lateral surface basal surfacemicrovilli that are as long as cilia nonmotile (unlike cilia)present in epithelial cells of ductus epididymishair cells of inner ear.Ductus epididymis, x 400

surface epithelium basal surface apical surface lateral surface

covering epithelium: surface modification of cells a.k.a., intercellular junctions; cell-to-cell attachments; junctional complexes

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmsurface epitheliumzonula occludensmost apically situatedzonula adherenslocated just below zonula occludensdesmosomesusually situated just below zonula adherensgap junctions. basal surface apical surface lateral surface

covering epithelium: surface modification of cells

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmsurface epitheliumbind cells togetherenable cells to communicatezonula occludensmost apically situatedzonula adherenslocated just below zonula occludensdesmosomesusually situated just below zonula adherensgap junctions. a.k.a., tight junctionband that completely surrounds cellcell membranes of adjacent cells eitherstick togetherfuse forming a trilaminar membrane. basal surface apical surface lateral surface

covering epithelium: surface modification of cells

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmsurface epitheliuma.k.a., belt desmosome; band desmosome also forms band around cell

zonula occludenszonula adherensdesmosomesgap junctions. cell membranesseparated by 15-20nm space filled with unknown material that binds membranesinternal surface of membranes contain fine filaments where terminal web insertsterminal webpresent in cells w/ microvilli or cilialayer of actin & intermediate filaments.

apical surface lateral surface

basal surfacecovering epithelium: surface modification of cells

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmsurface epitheliuma.k.a., macula adherens; spot desmosomeusually below zonula adherens, but may be in other areas

zonula occludenszonula adherensdesmosomesgap junctions. does not form a bandin epidermis -numerous and are the only junctional complex. apical surface lateral surface basal surfacecovering epithelium: surface modification of cells

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmovoid protein disc arranged in a line around cellhalf of disc attached to inner surface of cell membrane of one cellother half to inner surface of neighboring cellin LM, appear as thickenings of cell membrane intercellular spacewide ( > 30nm)contains transverse filamentsinside cells, intermediate filaments converge into half-disc.surface epithelium

broad areasmembranes closely apposed, but not fusedintercellular space, only 3 nm wide.

connexonsnumerous tiny tubes in apposed plasma membranesaligned with each otherallows exchange of ions and small molecules.

zonula occludenszonula adherensdesmosomesgap junctions. apical surface lateral surface basal surfacecovering epithelium: surface modification of cells http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmhttp://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmsurface epitheliumzonula occludenszonula adherensdesmosomesgap junctions. apical surface lateral surface basal surfacecovering epithelium: surface modification of cells hemidesmosomes basal infoldings of the plasmalemma apical surface lateral surface basal surfacesurface epitheliumin stratum basale of epidermisstructurally identical to half a desmosome help anchor epithelial cells to basal lamina apical surface lateral surface basal surfacecovering epithelium: surface modification of cells hemidesmosomes basal infoldings of the plasmalemma

http://images.google.com.ph/images?hl=en&lr=&ie=ISO-8859-1&q=hemidesmosome&btnG=Searchsurface epithelium apical surface lateral surface basal surfacecovering epithelium: surface modification of cells hemidesmosomes basal infoldings of the plasmalemma

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmin cells lining some segments of renal tubuleseen as basal striations loaded with mitochondriaincreases absorbing capacity of cells.

surface epitheliumcovering epithelium: surface modification of cells surface epitheliumcovering epitheliumlining epithelium glandular epitheliumproduces secretions (substances needed by body)surface epithelium apical surface lateral surface basal surfacehemidesmosomes basal infoldings of the plasmalemma

http://cellbio.utmb.edu/microanatomy/epithelia/epith_lec.htmin cells lining some segments of renal tubuleseen as basal striations loaded with mitochondriaincreases absorbing capacity of cells.

Epithelium : General Classificationsurface epitheliumcovering epitheliumlining epithelium glandular epitheliumproduces secretions (substances needed by body)glandular epitheliumEpithelium : General Classificationglandular epitheliumforms functional component of organs called glandsglands produce/synthesize substances (secretions) that are needed by body.

glandular epitheliumforms functional component of organs called glandsglands produce/synthesize substances (secretions) that are needed by body.

glandsglands: typesglands: typesexocrine glandsdeliver secretions on covering or lining epitheliumdirectlyvia a tube (duct) that serves as passageway for secretion from its production site (secretory cells) to surface endocrine glandsdeliver their secretion (hormone) into blood or lymph no excretory duct. endocrine glandsexocrine glandsdeliver secretions on covering or lining epitheliumdirectlyvia a tube (duct) that serves as passageway for secretion from its production site (secretory cells) to surface endocrine glandsdeliver their secretion (hormone) into blood or lymph no excretory duct. glands: typesendocrine glandsusually arise in embryo as invagination or evagination of epitheliumas a rule, initially with duct, but later severedoccur as:distinct organs e.g., pituitary, thyroid, etc.component of organs e.g., islets of Langerhans.

endocrine glandshormonesecretory productchemical messengerbrought by blood to target tissue/s or cell/s with appropriate receptors.

exocrine glandsdeliver secretions on covering or lining epitheliumendocrine glandsdeliver their secretion (hormone) into blood or lymph glandular epithelium: typesendocrine glandsglandular epitheliumexocrine glandsdeliver secretions on covering or lining epitheliumendocrine glandsdeliver their secretion (hormone) into blood or lymph exocrine glands: typesunicellular glandmulticellular gland exocrine glands: classificationunicellular glandunicellular glande.g., mucous or goblet cellin GI and respiratory tracts columnar cell; cup-shaped in histo prepssecretory vesicleson theca (apical portion)coalesce on histo prep and area becomes palenumerous; pushes organelles toward basemembrane-boundcontain mucin- glycoprotein which becomes mucus when hydrated.

http://www.gen.umn.edu/faculty_staff/jensen/1135/Histology/epithelial.htmlunicellular glandunicellular glandmulticellular gland

exocrine glands: classificationexocrine glandsmulticellular glandsunicellular glandmulticellular gland : classificationmulticellular glands with ductssecretory epithelial sheet e.g., the ependyma - simple cuboidal epithelium that lines cavities of CNSintraepithelial gland groups of secretory cells that gather around a small orifice that serves as a duct form shallow invaginations within epithelial surfaceseen in penile urethraglands with ductsmulticellular glands: types

parts:secretory portion - lie beneath epithelium duct or a system of ducts.

http://pathology.mc.duke.edu/research/histo_course/ependyma.jpghttp://www.udel.edu/biology/Wags/histopage/colorpage/cre/creignm.GIFmulticellular glands with ductsClassification: according to complexity of duct/ssimpleunbranched ductcompoundduct has branches.

http://www.science.ubc.ca/~biomania/tutorial/exogland/outanc03.htm Classification : according to morphology of secretory portion

Classificationmulticellular glands with ducts

tubular secretory portion is in form of blind-ending tube. alveolar or acinous secretory portion is globular or basket-like.tubuloalveolar some of secretory potions are tubular and some are globular.

http://www.science.ubc.ca/~biomania/tutorial/exogland/outanc03.htm Classification : according to morphology of secretory portion

Classificationmulticellular glands with ducts

http://www.science.ubc.ca/~biomania/tutorial/exogland/outanc03.htmthe secretory portion of some glands can be further classified into either branched or coilede.g. simple, coiled tubular gland.

examples (based on morphology of duct and secretory portion):multicellular glands with ductssimple tubular gland, large intestine, x100simple branched alveolar gland, sebaceous gland, x 100

examples (based on morphology of duct and secretory portion):multicellular glands with ductssimple branched tubular gland, stomach, pylorus, x100simple coiled tubular gland, sweat gland, x100

mucous glands produce viscous secretion that contains mucin substance rich in glycoproteinsforms mucus when hydrated, a thick fluid that protects and lubricates covering epithelia serous glands produce watery secretion that often contains enzymes mixed glandsproduce both viscous and watery secretions. Classification: according to nature of secretion

multicellular glands with ducts

multicellular glands with ductsof secretory portion (alveoli; acini)mucous alveoli (acini) serous alveoli (acini)mixed alveoli (acini).secretory portions consists entirely of mucous cellsmucous cellssecretory granules poorly preserved and stained pale-staining cytoplasmnucleus displaced to basal area.http://www.udel.edu/Biology/Wags/histopage/colorpage/co/cosgma.GIFsublingual gland Classification:

Classificationmulticellular glands with ductsof secretory portion (alveoli; acini)mucous alveoli (acini) serous alveoli (acini)

submandibular gland, x400mixed alveoli (acini).

secretory portion consists entirely of serous cellsserous cellscolumnar with basophilic cytoplasm secretory granules take up dye.nucleus spherical and basal in location.

Classificationmulticellular glands with ductsof secretory portion (alveoli; acini)submandibular gland, x400mucous alveoli (acini) serous alveoli (acini)mixed alveoli

secretory units contain mucous and serous cells in some glands, like submandibular glands, serous cells form crescentic caps at periphery of alveoli called demilunes (of Giannuzzi).

Classification: according to mode of secretion

multicellular glands with ductsmerocrine glands release secretion by exocytocis no loss of any part of celle.g., salivary glands holocrine glandsdestruction of entire cells; remnants of cells discharged together with secretions e.g., sebaceous gland apocrine glandsapical part of cell is released with secretory producte.g., ceruminous glands.

http://www.science.ubc.ca/~biomania/tutorial/exogland/outanc03.htmin secretory portions (alveoli or acini) and small ducts of sweat, mammary, salivary and some other glandsflattened, stellate cells processes between secretory cells and basal laminaembrace secretory alveoli and ductscontain contractile actin and myosin filaments contractions eject secretions of acini into ducts.

http://www.meddean.luc.edu/lumen/MedEd/Histo/frames/Histo13.htmlhttp://www.louisville.edu/medschool/anatomy/histology/eye/eye_img/Figure62.jpgLacrimal gland, 1- alveoli;2-duct3-myoepithelial cellmyoepithelial cellsTHANK YOU!!Closing PrayerHeavenly Father as we come to the end of our time together we thank you for what has been accomplished here today. May the matters discussed serve as a catalyst to move us forward and cause us to advance and see growth in all areas of our lives. May we leave here recognizing You are the God of all wisdom and You are willing to lead us forward. This we pray in the name of the Lord Jesus. AmenLet us remember that we are in the holy presence of GOD.In the name of the Father and of the Son and of the Holy Spirit. Amen.Saint John Baptist de la Salle, Pray for us.Live Jesus in our hearts, Forever.

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2. Epithelial Tissue14.Lect