SUMMARY
基礎醫(yī)學

        Epithelialtissuesarecomposedofcloselyaggregatedpolyhedralcellswithverylittleextracellularsubstance.Animportantfeatureofepitheliaistheirpolarity:theyhaveafreesurfaceandabasalsurfacethatrestonthebasalmembrane.Sincebloodvesselsdonotnormallypenetrateanepithel    （共 1229 字）     [閱讀本文] >>