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ID:43950559
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页数:5页
时间:2019-10-17
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1、AqueousproductionAqueoushumourisproducedfromplasmabytheciliaryepitheliumoftheciliarybodyparsplicata,usingacombinationofactiveandpassivesecretion(既有主动分泌也有被动运输).Ahigh-proteinfiltratepassesoutoffenestratedcapillaries(ultrafiltration)intothestromaoftheciliaryp
2、rocesses,fromwhichactivetransportofsolutes([容质)occursacrossthedual-layeredciliaryepithelium.Theosmoticgradienttherebyestablishedfacilitatesthepassiveflowofwaterintotheposteriorchamber.Secretionissubjecttotheinfluenceofthesympatheticnervoussystem,withopposi
3、ngactionsmediatedbybeta-2receptors(increasedsecretion)andalpha-2receptors(decreasedsecretion)(互相扌吉抗调节).Enzymaticactionisalsocritical一carbonicanhydrase(碳酸酶)isamongthoseplayingakeyrole.[l]Thetrabecularmeshwork(小梁网)(trabeculum)isasieve-like(筛状)structureatthea
4、ngleoftheanteriorchamber(AC)throughwhich90%ofaqueoushumourleavestheeye.Ithasthreecomponents.Theuvealmeshwork(葡萄网)istheinnermostportion,consistingofcord-like(索状)endothelialcell-coveredstrandsarisingfromtheiris(虹月莫)andciliarybodystroma.Theintertrabecular(小梁)
5、spacesarerelativelylargeandofferlittleresistancetothepassageofaqueous.Thecorneoscleralmeshworkliesexternaltotheuvealmeshworktoformthethickestportionofthetrabeculum.Itiscomposedoflayersofconnectivetissuestrandswithoverlyingendothelial-likecells.Theintertrab
6、ecularspacesaresmallerthanthoseoftheuvealmeshwork,conferringgreaterresistancetoflow.Thejuxtacanalicular(cribriform)meshworkistheouterpartofthetrabeculum,andlinksthecorneoscleralmeshworkwiththeendotheliumoftheinnerwallofthecanalofSehlemm.Itconsistsofcellsem
7、beddedinadenseextracellularmatrixwithnarrowintercellularspaces,andoffersthemajorproportionofnormalresistancetoaqueousoutflow・TheSchlemmcanalisacircumferentialchannelwithintheperilimbalsclera.Theinnerwallislinedbyirregularspindle-shapedendothelialcellsconta
8、ininginfoldings(giantvacuoles)thatarethoughttoconveyaqueousviatheformationoftranscellularpores-Theouterwallislinedbysmoothflatcellsandcontainstheopeningsofcollectorchannels,whichleavethecanalatobliqueanglesan
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