The human body is a dynamic place. Blood pumps, spinal fluid flows, oxygen comes in and carbon dioxide goes out. Deeper still, charged molecules pass through cell walls, quietly keeping the body's systems in balance. A new study from Northeastern University researchers published in the Proceedings of the National Academy of Sciences now unlocks a primary mechanism in how the body maintains its electrochemical balance through chloride ions, important in our most basic cellular functions. An imbalance in the body's electrochemistry can lead to diseases as diverse as high blood pressure or asthma.