Integrityofthemembranouslabyrinthbarriersystemisofcriticalimportance,whichpromotesinnerearhomeostasisandmaintainsitsfeatures.Themembranouslabyrinthbarriersystemispidedintoseveralsubsetsofbarrierswhich,althoughindependentfromeachother,areinterrelated.Thesamesubstancemaydemonstratedifferentpermeabilitycharacteristicsthroughdifferentbarriersandunderdifferentconditions,whiledifferentsubstancescanhavedifferentpermeabilityfeatureseveninthesamebarrierunderthesamecondition.Allpartsofthemembranouslabyrinthbarrierstructure,includingtheirmorphology,enzymesandchannelproteins,andtheirspermeabilitycharacteristicsundervariousphysiologicalandpathologicalconditionsarereviewedinthispaper.Infections,noiseexposure,ototoxicitymayallincreasepermeabilityofthebarriersandleadtodisturbancesininnerearhomeostasis.