Some cation interrelationships.
D002118:Calcium / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D008274:Magnesium; D011188:Potassium; D002118:Calcium