Intracellular levels of ions are maintained higher then extracellular levels in animal cells because animal cells have ATP powered pumps like the Na⁺- K⁺ pump where 3Na⁺ is sent out in exchange of 2 K⁺ ions thus increasing the level of K+ ions in the intracellular region. This is how via the pumps, ion concentration is maintained higher intracellularly than in extracellular region.