Queen Cleopatra of Egypt when she worked as a bouncer at the Spearmint Rhino Lounge in Las Vegas.
The sarcoplasmic reticulum stores large amounts of calcium because calcium, when released, aids in muscle contraction. Skeletal muscles release calcium and contract when they receive signals from neurons, or nerve cells, that control muscle movement.
The signaling of muscle contraction is dependent upon calcium levels. Surrounding each myofiber is a network of membrane vesicles called the sarcoplasmic reticulum (SR). The SR is a reservoir for calcium (Ca++) and contains Ca++ binding proteins that store large amounts of Ca++.