Practical1:LymphoidTissue&Organs PrincipalTeacher:DrMarkHill Objectives 1. Understandthemajorcelltypesofbloodastheyappearinbloodsmears 2. Understandthehistologyandorganizationoflymphoidorgans(thymus,spleen,lymphnodes) 3. Understand the histology and organization of lymphoid tissue, particularly that associated with the gastrointestinaltract. Resources VirtualSlideBoxUNSWBloodandLymphoidhistology http://vslides.unsw.edu.au/virtualslidev2.nsf/id/fa8942 UIOW http://www.path.uiowa.edu/cgibinpub/vs/fpx_browse.cgi?cat=o_hemato&div=nlm UNSWEmbryology http://php.med.unsw.edu.au/embryology/index.php?title=sh_practical Lymphatic_Structure_and_Organs Kierszenbaum,A.L.(2002).Chapter6;BloodandHematopoiesis&Chapter10;ImmuneLymphaticSystemin HistologyandCellBiology:AnIntroductiontoPathology.(1 st ed.,pp147175;pp267298).philadelphia,pa. Mosby,Elsevier. Introduction Thispracticalclasshas2mainparts.Thefirstpartwillbrieflyrevisethecellularcomponentsofbloodandtheir development. The second part will look in more detail at the organs and tissues associated with lymphoid (lymphatic)immunefunction.thepracticalinvolvesstudyingselectedslidesfromthevirtualslidebox.some textinthesepracticalnotesmodifiedfromvirtualslideboxhistology.additionalonlineselfdirectedlearning resourcesareavailablefromunswembryologypage(addressabove)includingexternalresourceandglossary links. Blood Thecirculatingbloodisaliquidconnectivetissueconsistingofcells(redandwhitebloodcells),fragmentsof cells (platelets) and liquid (plasma). The different cell types are all derived from haemopoietic stem cells locatedinthebonemarrow.redbloodcells(rbcs)haveametabolicrole,incarryingoxygentotissuesand carbondioxidetothelungs.whitebloodcells(wbcsorleukocytes)havearoleinthebody sdefence,andare animportantclinicalindicatorofdisease. VirtualSlideBox:1.HumanBloodSmear Findanareainthesmearwheretheredbloodcellsarespreadoutandindividualcellscanbeidentified. Identify:Redbloodcells(78umdiameteranucleatebiconcavedisc) Whitebloodcells:neutrophils,eosinophils,basophils,lymphocytesandmonocytes. (basophilsarenormallyrare).notethepresenceorabsenceofgranules,shapeofthenucleusandrelativecell sizes.alsoidentifyplatelets. MFAC1527: Society&Health StudentPracticalManual2013 Page7
VirtualSlideBox:2.BoneMarrowSmear Donotattempttoidentifyallthecellsinthebonemarrowsmear,butcompareitsappearancewiththatofthe bloodsmear. Hematopoiesisistheprocessofbloodcelldifferentiationandoccursmainlyinthebonemarrow.Thisbone marrow smear will contain a large number of differentiating blood cells: band cells and normoblasts. The largestcellsvisiblearemegakaryocytes,whichareresponsibleforplateletproduction. Lymphocytedifferentiationbeginsinthebonemarrowandcontinuesincentrallymphoidorgans(bonemarrow BcellsandthymusTcells),thenintheperipherallymphoidorgans(lymphnodes,spleen). Questions 1. Whatisthenormalbloodhaematocritrange? 2. Doesthishaematocritdifferformale/female? 3. Whatisthefunctionofthevariousbloodcells? 4. Whichtissueshaveverylargenumbersofwhitebloodcellsandwhy? 5. Inhistologytissuesectionswhichbloodvessel(artery/vein)ismorelikelytocontainbloodcells? LymphoidTissue Lymphoid(orlymphatic)tissuesconsistofdenseaccumulationsoflymphocytesinmanydifferentbodyregions, typicallyatsitesthatprovidearouteofentryofpathogensorsitesthatarepronetoinfections.dependingon theirpreciselocationtheselymphoidtissuesmaybeepitheliaassociatedandreferredtoasmucosaassociated lymphoidtissue(malt)orbronchusassociatedlymphoidtissue(balt).thegastrointestinaltracttonsilsand Peyer'spatchesareexamplesofmucosaassociatedlymphoidtissues. VirtualSlideBox:3.InfantThymus Sectionofathymuslobeofaninfant. Thethymuschangesitshistologicalappearancefrominfanttopubertytoadult,inaprocesscalledinvolution (replacementofcorticallymphoidtissuebyadiposetissue)andthereisalsoanincreaseinthesizeofthymic corpuscles. Atlowmagnification:notethesurroundingconnectivetissuecapsulealongthesurface.Thethymusisdivided intomanysmallerlobulesbyconnectivetissueseptaextendinginwardfromthecapsule.theselobueshavea cortex(darkstaining)andamedulla(palestaining).theinterlobularseptadonotpenetrateintothemedulla, andlobulesarejoinedtogetherinthemedulla.someseptamaycarrybloodvesselsandefferentlymphatic vessels. Athighmagnification:Cortexhasadenselayerofcloselypackedcells(developingandmaturingTlymphocytes, thymocytes).medullaconsistofaneosinophiliccentralmasssurroundedbyconcentricallyarrangedepithelial cells(hassallscorpuscles).donotconfusethemwithbloodvessels. MFAC1527:Society&Health StudentPracticalManual2013 Page8
Comparetheappearanceoftheinfantwiththeadultthymus(below). VirtualSlideBox:4.AdultThymus VirtualSlideBox:5.Spleen Thespleeninfetallifeisasiteforbloodformation(hematopoiesis).Theadultspleenhas2mainfunctions: immune,asamajorsiteofantigenpresentationforthecirculationsystemandremovalofagederythrocytes fromthecirculation.thespleenhasadenseconnectivetissuecapsule,whichcontainstrabeculaerunninginto the interior of the spleen forming incomplete compartments (as in the thymus). The stroma is mainly composed of reticular connective tissue and cells. There is a Hilum, which contains arteries and veins, but unlikealymphnode,therearenolymphatics.itshouldalsobenotedthatthespleencannotbedividedintoa medullaandcortex,whichhelpsdifferentiateitfromthethymusoralymphnode. Thespleenisamajorsiteofantigenpresentationforthecirculationsystem,andinfetallife,itisasitefor hematopoiesis. It also functions in removing senescent erythrocytes from the circulation. The spleen is surroundedbyadenseconnectivetissuecapsule,whichcontainstrabeculaerunningintotheinteriorofthe spleenformingincompletecompartments.thestromaismainlycomposedofreticularconnectivetissueand cells.thereisahilum,whichcontainsarteriesandveins,butunlikealymphnode,therearenolymphatics.it shouldalsobenotedthatthespleencannotbedividedintoamedullaandcortex,whichhelpsdifferentiateit fromthethymusoralymphnode. Identifyconnectivetissuecapsule,trabeculae,whitepulp,redpulp,lymphaticnodules,andcentralarterioles. The two main interior divisions of the spleen are white and red pulp. White pulp consists of a sheath of lymphoid cells surrounding an eccentrically located central arteriole. The T lymphocytes immediately surroundingthecentralarteriolearereferredtoasperiarteriallymphaticsheaths(pals).surroundingthatisa layerofperipheralwhitepulp(pwp),whichiscomposedofblymphocytes.antigenentersthewhitepulpfrom thecentralarteriole,activatesthepals,whichthenactivatesthepwp.themarginalzoneontheperipheryof thewhitepulpisbelievedtobeanimportantareafortrappingantigensandinitiationofimmuneresponses. Bothlymphocytesandmacrophagesarepresentinthemarginalzone. The red pulpconsists of splenic cords ofbillroth and splenic sinusoids. The splenic cords of Billroth contain reticularcells,macrophages,lymphocytes,plasmacells,anderythrocytes.thesplenicsinusoidsaremodified capillaries with an exceptionally wide lumen and spaces in the wall to allow cells to squeeze in and out. Macrophages are also able to extend processes into the sinusoid, allowing them to identify senescent red bloodcells. Blood enters the spleen via the splenic artery at the hilum. The blood then travels through the trabecular arteries,centralarterioles,penicillararterioles,capillaries,splenicsinusoids,trabecularveins,andfinallyout thesplenicveinatthehilum. MFAC1527: Society&Health StudentPracticalManual2013 Page9
VirtualSlideBox:5.Spleen (monkeysilverstain) Spleen silverstained to show connective tissue reticular fibers (black), compare this with the silverstained lymphnode. VirtualSlideBox:6.LymphNode Lymphnodesareperipherallymphoidorgansinvolvedinhelpingthebodydefendagainstforeignorganisms. Lymph, which contains antigen and antigen presenting cells, flows from local tissue lymphatic vessels and enters the subcapsular sinus. The lymph then filters though the intermediate sinuses, into the medullary sinuses,andfinallyouttheefferentlymphaticvesselsatthehilumbeforeitisreturnedtothecirculation.band Tcellsarenumerousinthelymphnode,andtheyenterthroughafferentarteries,enterthelymphoidaltissue acrossspecializedvesselscalledhighendothelialvenules,andreturntothecirculationviaefferentveins. Identify the following features: the connective tissue capsule, the trabeculae, the subcapsular sinus (lying immediatelybelowthecapsule),theintermediatesinus(lyingnexttoatrabecula),outercortex(composedof lymphaticnodules follicles),the innercortex (nonnodular areabetween outercortex and medulla) andthe medulla(withmedullarycordsandmedullarysinuses). VirtualSlideBox:7.LymphNode(silverstain) Lymphnodesilverstainedtoshowconnectivetissuereticularfibers(black). Identifyreticularfiberdistributionin:capsule,trabeculae,subcapsularsinuses,intermediatesinuses,lymphoid nodules,theinnercortex,andthemedulla. VirtualSlideBox:8.Lingualtonsil(tongue) MFAC1527:Society&Health StudentPracticalManual2013 Page10
The lingual tonsils are numerous small tonsils located at the base of the tongue. They are covered by a stratified squamous epithelium, but are not enclosed by a capsule. Salivary glands and skeletal muscle are directlyadjacenttothetonsil. VirtualSlideBox:9.Pharyngealtonsil Closelypackedlymphnodulescomprisetheouterportionofthisorgan.Thepharyngealtonsiliscoveredwitha pseudostratifiedcolumnarepitheliumwithcilia(typicalofrespiratorytract). VirtualSlideBox:10.Appendix Theappendix(vermiformappendix)anatomyisasafingerlikestructurethatarisesfromthececum.Thelength (2.513cm)islongerinbothinfantsandchildrenandalsohasmoreabundantlymphatictissueinearlylife.The wallstructureissimilartothesmallintestine(thoughwithnovilli),norplicaecircularis. Lymph nodules surround the lumen of the gastrointestinal tract and extend from the mucosa into the submucosa.noteinthissectionmostofthemuscularismucosahasbeenobliteratedbylymphaticinvasion. Questions 1. Whatisthedifferencebetweenstromaandparenchyma? 2. Whichcellsmakereticularfibers? 3. Whyarelymphoidtissuesassociatedwiththegastrointestinaltractandrespiratorytissues? 4. Whatisanantigenandwhatdoesitproduceintheimmunesystem? 5. Wherecantonsilartissuebefoundinthegastrointestinaltract? MFAC1527: Society&Health StudentPracticalManual2013 Page11
Practical2:GroupProject:IntroducingSPSS PrincipalTeacher:DrRachelThompson Aims TolearnthebasicsofSPSSdatahandlingandanalysis Tocleanthedataintheolddatasetandpracticehandlingandanalysingthedata KeyConcepts Parametricandnonparametricstatistics,correlation,chisquare,ttest KeyReferences UCLAAcademicTechnicalServices.IntroductiontoSPSS:AnalyzingData.Part1. http://www.ats.ucla.edu/stat/spss PracticalNotesforthisclassareavailableonlinefromtheQMPBlackboardcourseordirectlyfrom http://web.med.unsw.edu.au/qmp/spssdtahandling/dataprac_objectives.htm MFAC1527:Society&Health StudentPracticalManual2013 Page12