Sodium and potassium occur in all known biological systems, generally functioning as electrolytes inside and outside cells.
sˈoʊdiəm ænd pətˈæsiəm əkˈɜːɹ ɪn ˈɔːl nˈoʊn bˌaɪəlˈɑːdʒɪkəl sˈɪstəmz, dʒˈɛnɚɹəli fˈʌŋkʃənɪŋ æz ᵻlˈɛktɹəlˌaɪts ɪnsˈaɪd ænd aʊtsˈaɪd sˈɛlz.