Can someone please explain the balance of sodium and potassium in the body?
Sure. The balance of sodium and potassium is extremely important in the nervous system. When your nerve cell (neuron) is at rest, it is said to have a resting potential of -70mV. What this means is that neurons are more negative inside than outside. This is done by an enzyme called Na+/K+ ATPase, also called the sodium-potassium pump. Using energy (active transport) it takes in two molecules of K+ for every 3 molecules of Na+ it sends out. Since there is more Na+ on the outside, its tendency is to follow the gradient and diffuse into the cell, but the membrane of neurons is selectively permeable, and prevents that from happing. So what ends up happening is that loads of Na+ ions are outside the cell, and loads, but slightly less K+ ions are in the cell, causing that negative potential. When the neuron is stimulated, Na+ enters, and the cell depolarizes a little bit and becomes more positive inside. If the internal charge reaches a certain amount, the neuron will fire an action potentia
