Why Are Sodium and Potassium Essential for Body Channels?

[aychamo]

So why did we end up using the elments that we use for body things? Specifically, Na and K for the channels. Why is it that these two ended up being used? What is it about their chemical characteristics that make them so good at what they do?

Also, with Ca, like you have Ca in your sarcoplasm, and that is what is used in striated muscle contraction (right?), so if you consume a lot of calcium, will it help your muscle strenght? Or I mean, if you don't concume much Ca, will your muscles atrophy? How do you maintain the health of your muscles? How does eating "protein" like in beef make your muscle stronger/better? From what I understand, striated muscle has satelite cells that divide and differentiate into muscle cells to repair injured muscle cells, this is how muscle mass increases with working out. So how does the other stuff (Ca, proteins, etc) fit in? Also, when you flex and unflex, the Ca moves in and out, is it continuously recycled or is sometimes it used up and can't be reused (thus needing more Ca)?

Also, for these ions that the body uses (Na, K, Ca, etc) is this all absorbed in the large intestine? Why is vitamin D neccesary to absorb Ca?

And sharing this love for Ca, what else is it used for in the body? I know its in for bone growth and remodeling, and for muscle contraction, what else?

:) <-- Tons of questions

 

[iansmith]

It is probably that due to our single cell ancestor. These cells evolves in a different environment. The best example and what I known the most about is iron. Iron is one most important thing for virtually all organism (there some few exception in bacteria). The problem is that iron is toxic in the presence of Oxygen. Iron will create free oxygen redicals which cause DNA damage. The iron metabolism was evolved before the atmosphere was 20% oxygen. Iron ion into prevalent oxydated forms (Fe2+ & Fe3+) have great redox potential. Iron is the fourth most abundant element within the Earth's crust. Na, Ca and K are in the top 10 (http://education.jlab.org/glossary/abund_ele.html). The abundance of the ions must have play a role in why these are use so widely in many organisms. Also Na, Ca and K are highly reactive elements.