# Electrolytes --- **Electrolytes** are [[substance|chemical compounds]] both dissolve *and* dissociate (i.e. the atoms separate) in [[water]]. This means there are now charged atoms floating around the fluid which allows that fluid to readily conduct [[electricity]]. This is very useful and essential for [[biology]]. Proper balance of electrolytes are essential for maintaining [[homeostasis]]. >[!science] Charge! >No matter the sourse, electrolytes are *always* charged, positively or negatively. [[Mineral]] salt electrolytes come in the form of [[atom#Ions and Isotopes|ion pairs]] that, if not in solution, form [[ionic bond|ionic bonds]] together. [[Acids and bases]] also act as electrolytes. For example: Acid: HCl (aq) → H$^+$ + Cl$^–$ Base: NaOH (aq) → Na$^+$ + OH$^–$ ## Function Electrolytes play many important roles in biology, including facilitating osmosis and providing the ability for nerves and other excitable cells to react. - The **cations** we use biologically are: - [[sodium]] (Na$^+$) - [[potassium]] (K$^+$) - [[calcium]] (Ca++) - magnesium (Mg+) - H+ >[!science] What do these ions do? >"Sodium in the brain, potassium in the heart" Na+ is big for regulating nurological functions, and K+ keeps the heart working. - The **anions** we use biologically are (though some are technically [[substance|chemical compounds]]...we still consider them ions because they're charged): - [[chloride]] (Cl$^-$) - [[phosphate]] (HPO$_4^{2-}$) - [[bicarbonate]] (HCO$_3^-$) - and 'A-' which is any generally negatively charged molecule, but practically always proteins. ![[electrolytes.png]] - **Osmosis** - Electrolyte balance is important in keeping [[osmosis|osmotic pressure]] stable in the cells. This is why diarrheic can be so harmful—water is lost but not electrolytes, causing cells to "dry out". - **Nerve Conduction** - Electrolytes help charge up [[neurons]] to fire their *action potentials*. - **Muscle Contractions** - Electrolytes so something that helps [[muscle tissue|muscle cells]] contract. Something about nerve cells releasing calcium that triggers a contraction. ## Problems With Electrolytes (i.e. Imbalances) Electrolyte imbalances can cause: - seizures - muscle cramps - muscle weakness - paralysis For example, sodium is the major extracellular cation. Sodium influx into cells causes depolarization of nerve and muscle cells, i.e., it makes them fire. More sodium = hyperexcitability = rapid heart rate and arrhythmias, muscle spasms (cramps), and seizures due to a hyperactive nervous system. Hyponatremia is going to make nerve and muscles less excitable due to slower influx of the positive cation = weakness, bradycardia, etc. You also have to consider how changes in electrolyte concentration will alter the movement of fluids, for instance, if you have a patient with SIADH or fluid volume overload that drives down the osmolarity of the blood and causes hyponatremia in the blood and interstitial fluids, you’ll have movement of water into cells, which can result in conditions like cerebral edema and anasarca. ___