Physiology General 79a4a0ee Skeletal muscle contraction ends when: A Ions move out of cytoplasm B Ach is absorbed from the NMJ C Closure and indrawing of receptors D Decreased calcium outside reticulum High-Yield Explanation “Once the Ca2+ concentration outside the reticulum has been lowered sufficiently, chemical interaction between myosin and actin ceases and the muscle relaxes.”