LensandCataractS11CH01Anatomy

鄭亞潔NormalCrystallineLensTransparent透明Biconvex雙凸noblood無(wú)血管noinnervation無(wú)神經(jīng)Metabolic新陳代謝：aqueoushumor房水posteriortotheirisandanteriortothevitreousbody位于虹膜后玻璃體前NormalCrystallineLensThelensiscomposedofthecapsule,lensepithelium,cortex,andnucleus晶體：囊，上皮細(xì)胞，皮質(zhì)，核opticaxis視軸穿過(guò)晶體前后極equator晶體赤道部周長(zhǎng)最長(zhǎng)

NormalCrystallineLensindexofrefraction折射率：中央centrally1.4周邊peripherally1.36非調(diào)節(jié)狀態(tài)lens晶體：15-20D總屈光度約60DCornea角膜40-45DNormalCrystallineLensThelenscontinuestogrowthroughoutlife.晶體一生持續(xù)生長(zhǎng)出生：6.4mm*3.5mm，90mg成人：9mm*5mm，255mg老年：皮質(zhì)增厚，晶體表面曲率增加

refractivepower屈光力增加晶體密度增加indexofrefraction折射率下降

結(jié)果：近視myopic/遠(yuǎn)視hyperopicNormalCrystallineLens透明transparent，有彈性elastic上皮細(xì)胞分泌的IV型膠原collagen晶狀體赤道前后最厚，后極中央最薄前囊出生時(shí)比后囊厚，且持續(xù)終生生長(zhǎng)Capsule囊LensEpithelium上皮細(xì)胞前囊下單層上皮細(xì)胞代謝活躍，合成：DNA,RNA,protein蛋白，lipid脂類(lèi)及ATP供能有絲分裂在germinativezone生發(fā)區(qū)最旺盛新細(xì)胞migrate遷移至equator赤道部，在bowregion弓形區(qū)最終分化成晶體纖維最戲劇性的變化：上皮細(xì)胞拉長(zhǎng)纖維細(xì)胞纖維細(xì)胞：膜蛋白大量增加；

細(xì)胞器減少（細(xì)胞核，線粒體，核糖體）利于光線穿過(guò)，不被吸收和阻擋糖酵解功能（缺少細(xì)胞器代謝）

LensEpithelium上皮細(xì)胞Perhapsthemostdramaticmorphologicchangeoccurswhentheepithelialcellselongatetoformlensfibercells.Thischangeisassociatedwithatremendousincreaseinthemassofcellularproteinsinthefibercellmembranes.Atthesametime,thecellsloseorganelles,includingcellnuclei,mitochondria,andribosomes.Thelossoftheseorganellesisopticallyadvantageous,becauselightpassingthroughthelensisnolongerabsorbedorscatteredbythesestructures.However,becausethesenewlensfibercellslackthemetabolicfunctionspreviouslycarriedoutbytheorganelles,theyarenowdependentonglycolysisforenergyproductionY字縫：前正Y頂端細(xì)胞突觸交錯(cuò)排列