Why do our bodies need potassium as an electrolyte if we already have sodium which helps our body absorb water and ensures our muscles work?
In: 16
The body uses several different metal ions for different purposes.
Calcium, potassium, sodium, iron, magnesium, manganese… just look at any mineral supplement and you will see a list of different metal ions used by the body. They aren’t interchangeable.
[Electrolytes](https://my.clevelandclinic.org/health/diagnostics/21790-electrolytes)
Potassium (+)
Your cells use potassium alongside sodium. When a sodium ion enters a cell, a potassium ion leaves, and vice versa. Potassium is also especially critical to your heart function. Too much or too little can cause serious heart problems.
Hyperkalemia (too much potassium): Weakness, inability to move muscles, confusion, irregular heart rhythms (arrhythmias).
Hypokalemia (not enough potassium): Muscle weakness and cramps, feeling unusually thirsty and needing to pee frequently, dizziness or passing out when standing up too quickly. At higher levels, muscle tissue begins to break down (a condition called rhabdomyolysis, which can severely damage your kidneys) and heart arrhythmias become a serious threat.
Living organisms started using potassium long before sodium. So, it is more appropriate to ask: why do we need sodium, if we already have potassium?
The reason is evolutionary history: land animals evolved from sea animals, and sea animals had access to sea water, which is rich in sodium. So they started using that easily accessible sodium in their biochemistry. By the time the animals went on shore, there was no going back – their nervous system became dependent on sodium – it started exploiting a difference between sodium and potassium for its work. Which is a problem for land animals – it is much more difficult to find sodium on land (and this is why we can taste salty things).
Plants have evolved differently, and sodium is not essential for them. It is possible, that if our ancestors didn’t live in sodium-rich environment, we wouldn’t depend on sodium also.
The sodium-potassium pump has the job of keeping the axon of neurons ready for the next electrical signal in the nervous system. With out this process, the electrical signals of the nervous system would not be able to travel from neuron to neuron. You experience this at a low level when you get muscle cramps.
The gradient between sodium and potassium also helps control the osmotic pressure inside cells, and powers a variety of other pumps that link the flow of sodium ions with the transport of other molecules, such as calcium ions or glucose.
Long story short with out potassium you are dead.
Latest Answers