And this is exactly where the calcium Atpas actually comes into play. Calcium Atpas uses ATP molecules to move these calcium ions against the electrochemical gradient. And calcium Atpas is also sometimes called circa, where the S and E stands for sarcoplas reticulum, slash, endoplasm, reticulum. The C stand, the the CA stands for calcium. So the Surf stands for sarcoplasmic endoplasmic, the R stands for reticulum, and the CA stands for calcium. Or perhaps the C stands for calcium.