So these calcium ions will travel down their electrochemical gradient end into our cytosol. Now, inside the muscle cell, we have many, many of these myofibrils. And what these myofibrils are, are basically our sarcomeres connected end to end. So we have many of these myofibrils. And if we examine one of these myofibrils and we zoom in on the myofibril, we basically get the following diagram. So, we have many of these sarcomeres connected end to end to form our myofibility.