ty(Fig.22.3)Protectionagainstbacteria,etc..Inthenoseandmouth.Threetypesoftonsils:pharyngeal,palatine,andlingualEnlargedpharyngealtonsiliscalledadenoid.LymphNodes(Fig.22.1andFig.22.4)Foundthroughoutthebodyexceptinthebrain.Theyareencapsulationoflymphocytes,macrophagesandreticularcellswithbloodvessels1-25mmindiameterandaresubdividedintotworegionscalled,amedullaandcortex.Withinthecortexgerminalcentersarefound.Thisiswherelymphocytedivisiontakesplace.Actassieveandremovalof99%ofantigenswhilereactivatingT-cellsandB-cells.TheSpleenUpperandposteriorpartoftheabdominalcavity.Largestofthelymphatictissue,160g.(Fig.22.5)Containstwotypesoflymphatictissue:whitepulp(arterialsupply)andredpulp(venoussupply).Thespleendetectsandrespondstoforeignsubstancesintheblood,destroysworn-outRBC’sandactsasabloodreservoir.
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