▁compreh ensive ▁list ▁is ▁available ▁at ▁the ▁United ▁Nations ▁System ▁article .) ▁ ▁Special ised ▁Organ izations ▁and ▁ag encies ▁ ▁The ▁United ▁Nations ▁maintain s ▁and ▁supports ▁a ▁number ▁of ▁special ized ▁organizations ▁and ▁ag encies . ▁These ▁differ ▁from ▁the ▁program mes ▁and ▁funds ▁in ▁that ▁they ▁are ▁head ed ▁by ▁an ▁executive ▁board ▁of ▁member ▁states , ▁separate ▁from ▁the ▁General ▁Assembly . ▁Sometimes ▁they ▁do ▁not ▁report ▁to ▁the ▁General ▁Assembly ▁or ▁Security ▁Council ▁but ▁only ▁to ▁their ▁own ▁member ▁states . ▁Some ▁of ▁these ▁bodies ▁also ▁pre date ▁the ▁United ▁Nations ▁as ▁is ▁the ▁case ▁for ▁the ▁IT U ▁formed ▁in ▁ 1 8 6 5 ▁to ▁admin ister ▁an ▁international ▁treat y ▁and ▁the ▁I LO ▁created ▁as ▁part ▁of ▁the ▁League ▁of ▁Nations . ▁ ▁Depart ments ▁and ▁offices ▁of ▁the ▁United ▁Nations ▁Secret ariat ▁ ▁The ▁United ▁Nations ▁Secret ariat ▁car ries ▁out ▁the ▁day - to - day ▁work ▁of ▁the ▁Organisation . ▁It ▁services ▁the ▁other ▁principal ▁org ans ▁of ▁the ▁United ▁Nations ▁and ▁admin ister s ▁the ▁program mes ▁and ▁policies ▁laid ▁down ▁by ▁them . ▁At ▁its ▁head ▁is ▁the ▁Secretary - General , ▁who ▁is ▁appointed ▁by ▁the ▁General ▁Assembly . ▁The ▁Secret ariat ▁admin ister s ▁a ▁number ▁of ▁notable ▁Off ices ▁and ▁Depart ments . ▁ ▁Tre aty ▁organis ations ▁ ▁The ▁United ▁Nations ▁maintain s , ▁admin ister s ▁or ▁has ▁a ▁working ▁relationship ▁with ▁a ▁number ▁of ▁organis ations ▁dedicated ▁to ▁the ▁administration ▁of ▁a ▁variety