where is calcium stored within a muscle cell
When muscles are at rest, calcium ions are stored in a cellular structure called the sarcoplasmic reticulum inside each muscle cell. In response to certain signals, the RYR1 channel releases calcium ions from the sarcoplasmic reticulum into the surrounding cell fluid (cytoplasm).The resulting increase in calcium ion concentration stimulates muscle fibers to contract, allowing the body to move.n response to certain signals, the RYR1 channel releases calcium ions from the sarcoplasmic reticulum into the surrounding cell fluid (cytoplasm). The resulting increase in calcium ion concentration stimulates muscle fibers to contract, allowing the body to move.