And so what the cell actually does is it uses these special membrane pumps, we call the calcium Atph to create electrochemical gradients, to basically pump these calciumines and store the calcium mines away from the proteins inside the cytoplasm. So we store these calciumines in the endoplasmic reticulum. And when we actually want to use the calcium ions, we have these membrane channels not shown diagram that can allow the movement of these calcium odds from the lumen into the cytoplasm of the cell. So we see that this is why the cell pumps out the majority of the calcium and stores it in the endoplasm reticulum until it is actually needed. Because if the calcium is allowed to exist, if lots of calcium is allowed to exist for long periods of time in the cytoplasm, that can cause protein precipitation. And so the intrinsically low levels of cytoplasm, of cytoplasmic calcium allows the cell to actually detect even the smallest changes of increases in calcium.