All electrolytes are ions that carry either a positive or negative charge. Negatively charged ions are called anions, and positively charged ones are called cations. When cations and anions dissociate in water and become capable of carrying electric currents, they are known as electrolytes. They are necessary to maintain the body's fluid balance inside and outside of cells. Some of the important ones in the body include sodium, potassium, and calcium ions.
Ions are atoms that have become electrically charged by gaining or losing an electron. Atoms are often neutral because they have an equal number of protons and electrons. Electrons have a negative charge, and protons have a positive charge. If an atom loses an electron, it therefore has a greater number of protons and carries a positive charge. An atom that gains an electron has a greater number of electrons and gains a negative charge.
The sodium (NA) cation is most important in regulating extracellular fluid. The sodium ion can be represented as Na+ because it carries a positive charge. In the regulation of extracellular fluid balance, Na+ concentration plays a role in the sensation of thirst and in alerting the kidneys to retain or excrete water. An increase in the concentration of sodium ions generally means that the volume of water in the body has temporarily decreased, and water will be retained. Decreased concentrations trigger the loss of excess water in urine.
The chloride anion (Cl-) is also important in maintaining extracellular fluid balance. Sodium and chloride ions are attracted by their opposite charges, so they aren't easily separated. As Na+ ions are also heavily present in the extracellular fluid, they are both affected by similar mechanisms.
Potassium ions (K+) are important in regulating the activity of cells that are sensitive to electrical impulses. The concentration of potassium ions is closely regulated. Calcium ions (Ca2+) levels are also tightly controlled. Similar to potassium, nerve cells are also sensitive to changes in the levels of Ca2+.
Changes in the levels of body electrolytes can cause imbalances. At their most severe, these disruptions can cause changes in mental states and disturb normal heart rhythm. They are usually rare in healthy people because the levels are closely maintained through a number of different pathways. Possible causes of imbalances include injuries, such as serious burns, and cases of severe diarrhea. They are more likely to occur in people with certain health conditions, such as diabetes or alcoholism.